Internet Key Exchange for IPsec VPNs Configuration Guide Cisco IOS Release 12.4T

Internet Key Exchange for IPsec VPNs

Configuration Guide Cisco IOS Release

12.4T

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Fax: 408 527-0883

C O N T E N T S

Configuring Internet Key Exchange for IPsec VPNs

1

Finding Feature Information

1

Prerequisites for IKE Configuration

1

Restrictions for IKE Configuration

2

Information About Configuring IKE for IPsec VPNs

2

Supported Standards for Use with IKE

2

IKE Benefits

4

IKE Main Mode and Aggressive Mode

4

IKE Policies Security Parameters for IKE Negotiation

4

About IKE Policies

4

IKE Peers Agreeing Upon a Matching IKE Policy

5

IKE Authentication

5

RSA Signatures

5

RSA Encrypted Nonces

6

Preshared Keys

6

Preshared Keys An Overview

6

ISAKMP Identity Setting for Preshared Keys

7

Mask Preshared Keys

7

Disable Xauth on a Specific IPsec Peer

7

IKE Mode Configuration

8

How to Configure IKE for IPsec VPNs

8

Creating IKE Policies

8

Troubleshooting Tips

12

What to Do Next

12

Configuring IKE Authentication

13

Configuring RSA Keys Manually for RSA Encrypted Nonces

13

Configuring Preshared Keys

17

Configuring IKE Mode Configuration

20

Configuring an IKE Crypto Map for IPsec SA Negotiation

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Internet Key Exchange for IPsec VPNs Configuration Guide Cisco IOS Release 12.4T ii

Contents

Configuration Examples for an IKE Configuration

22

Example: Creating IKE Policies

22

Example: Creating 3DES IKE Policies

22

Example: Creating an AES IKE Policy

23

Example: Configuring IKE Authentication

24

Where to Go Next

24

Additional References

24

Feature Information for Configuring IKE for IPsec VPNs

26

Call Admission Control for IKE

29


29

Prerequisites for Call Admission Control for IKE

29

Information About Call Admission Control for IKE

29

IKE Session

30

Security Association Limit

30

Limit on Number of In-Negotiation IKE Connections

30

System Resource Usage

30

How to Configure Call Admission Control for IKE

31

Configuring the IKE Security Association Limit

31

Configuring the System Resource Limit

32

Verifying the Call Admission Control for IKE Configuration

33

Configuration Examples for Call Admission Control for IKE

34

Example Configuring the IKE Security Association Limit

34

Example Configuring the System Resource Limit

34


34

Feature Information for Call Admission Control for IKE

35

Certificate to ISAKMP Profile Mapping

39


39

Prerequisites for Certificate to ISAKMP Profile Mapping

39

Restrictions for Certificate to ISAKMP Profile Mapping

39

Information About Certificate to ISAKMP Profile Mapping

40

Certificate to ISAKMP Profile Mapping Overview

40

How Certificate to ISAKMP Profile Mapping Works

40

Assigning an ISAKMP Profile and Group Name to a Peer

41

How to Configure Certificate to ISAKMP Profile Mapping

41

Mapping the Certificate to the ISAKMP Profile

41

Internet Key Exchange for IPsec VPNs Configuration Guide Cisco IOS Release 12.4T iii

Contents

Verifying That the Certificate Has Been Mapped

42

Assigning the Group Name to the Peer

43

Monitoring and Maintaining Your Certificate to ISAKMP Profile Mapping

43

Configuration Examples for Certificate to ISAKMP Profile Mapping

44

Certificates Mapped to the ISAKMP Profile on the Basis of Arbitrary Fields Example

44

Group Name Assigned to a Peer That Is Associated with an ISAKMP Profile Example

45

Mapping a Certificate to an ISAKMP Profile Verification Example

45

Group Name Assigned to a Peer Verification Example

46


47

Feature Information for Certificate to ISAKMP Profile Mapping

48

Encrypted Preshared Key

51


51

Restrictions for Encrypted Preshared Key

51

Information About Encrypted Preshared Key

52

Using the Encrypted Preshared Key Feature to Securely Store Passwords

52

Changing a Password

52

Deleting a Password

52

Unconfiguring Password Encryption

53

Storing Passwords

53

Configuring New or Unknown Passwords

53

Enabling the Encrypted Preshared Key

53

How to Configure an Encrypted Preshared Key

53

Configuring an Encrypted Preshared Key

54


55

Monitoring Encrypted Preshared Keys

55

What To Do Next

56

Configuring an ISAKMP Preshared Key

56

Configuring an ISAKMP Preshared Key in ISAKMP Keyrings

57

Configuring ISAKMP Aggressive Mode

58

Configuring a Unity Server Group Policy

59

Configuring an Easy VPN Client

61

Configuration Examples for Encrypted Preshared Key

62

Encrypted Preshared Key Example

62

No Previous Key Present Example

63

Key Already Exists Example

63

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Internet Key Exchange for IPsec VPNs Configuration Guide Cisco IOS Release 12.4T

Contents

Key Already Exists But the User Wants to Key In Interactively Example

63

No Key Present But the User Wants to Key In Interactively Example

63

Removal of the Password Encryption Example

63

Where to Go Next

64


64

Related Documents

64

Standards

64

MIBs

64

RFCs

64

Technical Assistance

65

Fragmentation of IKE Packets

67


67

Prerequisites for Fragmentation of IKE Packets

67

Restrictions for Fragmentation of IKE Packets

68

Information About Fragmentation of IKE Packets

68

How to Configure Fragmentation of IKE Packets

68

Configuration Examples for Fragmentation of IKE Packets

69


69

Feature Information for Fragmentation of IKE Packets

71

IKE Responder-Only Mode

73


73

Prerequisites for IKE Responder-Only Mode

73

Restrictions for IKE Responder-Only Mode

73

Information About IKE Responder-Only Mode

74

Benefits of the IKE Responder-Only Mode Feature

74

How to Configure IKE Responder-Only Mode

74

Configuring a Device As IKE Responder-Only

74

Configuration Examples for IKE Responder-Only Mode

75


75

Feature Information for IKE Responder-Only Mode

76

Distinguished Name Based Crypto Maps

79


79

Feature Overview

79

Benefits

80

Restrictions

80

Internet Key Exchange for IPsec VPNs Configuration Guide Cisco IOS Release 12.4T v

Contents

Related Documents

80

Supported Platforms

80

Supported Standards MIBs and RFCs

81

Prerequisites

81

Configuration Tasks

81

Configuring DN Based Crypto Maps (authenticated by DN)

82

Configuring DN Based Crypto Maps (authenticated by hostname)

82

Applying Identity to DN Based Crypto Maps

82

Verifying DN Based Crypto Maps

83


83

Configuration Examples

83

DN Based Crypto Map Configuration Example

83

IPsec and Quality of Service

85


85

Prerequisites for IPsec and Quality of Service

85

Restrictions for IPsec and Quality of Service

86

Information About IPsec and Quality of Service

86

IPsec and Quality of Service Overview

86

How to Configure IPsec and Quality of Service

86

Configuring IPsec and Quality of Service

86

Verifying IPsec and Quality of Service Sessions

87


88

Configuration Examples for IPsec and Quality of Service

88

QoS Policy Applied to Two Groups of Remote Users Example

88

show crypto isakmp profile Command Example

90

show crypto ipsec sa Command Example

90


91

Related Documents

91

Standards

91

MIBs

91

RFCs

91

Technical Assistance

92

Feature Information for IPsec and Quality of Service

92

VRF-Aware IPsec

95


95

vi


Contents

Restrictions for VRF-Aware IPsec

95

Information About VRF-Aware IPsec

96

VRF Instance

96

MPLS Distribution Protocol

96

VRF-Aware IPsec Functional Overview

96

Packet Flow into the IPsec Tunnel

97

Packet Flow from the IPsec Tunnel

97

How to Configure VRF-Aware IPsec

98

Configuring Crypto Keyrings

98

Configuring ISAKMP Profiles

100

What to Do Next

104

Configuring an ISAKMP Profile on a Crypto Map

104

Configuring to Ignore Extended Authentication During IKE Phase 1 Negotiation

106

Verifying VRF-Aware IPsec

106

Clearing Security Associations

107

Troubleshooting VRF-Aware IPsec

108

Debug Examples for VRF-Aware IPsec

109

Configuration Examples for VRF-Aware IPsec

115

Example Static IPsec-to-MPLS VPN

116

Example IPsec-to-MPLS VPN Using RSA Encryption

117

Example IPsec-to-MPLS VPN with RSA Signatures

119

Example IPsec Remote Access-to-MPLS VPN

120

Upgrade from Previous Versions of the Cisco Network-Based IPsec VPN Solution

121

Site-to-Site Configuration Upgrade

121

Previous Version Site-to-Site Configuration

121

New Version Site-to-Site Configuration

122

Remote Access Configuration Upgrade

122

Previous Version Remote Access Configuration

122

New Version Remote Access Configuration

123

Combination Site-to-Site and Remote Access Configuration Upgrade

124

Previous Version Site-to-Site and Remote Access Configuration

124

New Version Site-to-Site and Remote Access Configuration

125


126

Feature Information for VRF-Aware IPsec

127

Glossary

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Internet Key Exchange for IPsec VPNs Configuration Guide Cisco IOS Release 12.4T vii

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IKE Initiate Aggressive Mode

131


131

Prerequisites for IKE Initiate Aggressive Mode

131

Restrictions for IKE Initiate Aggressive Mode

132

Information About IKE Initiate Aggressive Mode

132

Overview

132

RADIUS Tunnel Attributes

132

How to Configure IKE Initiate Aggressive Mode

132

Configuring RADIUS Tunnel Attributes

133

Verifying RADIUS Tunnel Attribute Configurations

134


134

Configuration Examples for IKE Initiate Aggressive Mode

135

Hub Configuration Example

135

Spoke Configuration Example

136

RADIUS User Profile Example

136


136

Feature Information for IKE Initiate Aggressive Mode

137

viii


Contents

Internet Key Exchange for IPsec VPNs Configuration Guide Cisco IOS Release 12.4T ix

Configuring Internet Key Exchange for IPsec

VPNs

This module describes how to configure the Internet Key Exchange (IKE) protocol for basic IP Security

(IPsec) Virtual Private Networks (VPNs). IKE is a key management protocol standard that is used in conjunction with the IPsec standard. IPsec is an IP security feature that provides robust authentication and encryption of IP packets.

IPsec can be configured without IKE, but IKE enhances IPsec by providing additional features, flexibility, and ease of configuration for the IPsec standard.

IKE is a hybrid protocol, that implements the Oakley key exchange and Skeme key exchange inside the

Internet Security Association Key Management Protocol (ISAKMP) framework. (ISAKMP, Oakley, and

Skeme are security protocols implemented by IKE.)

•

Finding Feature Information, page 1

•

Prerequisites for IKE Configuration, page 1

•

Restrictions for IKE Configuration, page 2

•

Information About Configuring IKE for IPsec VPNs, page 2

•

How to Configure IKE for IPsec VPNs, page 8

•

Configuration Examples for an IKE Configuration, page 22

•

Where to Go Next, page 24

•

Additional References, page 24

•

Feature Information for Configuring IKE for IPsec VPNs, page 26

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support.

To access Cisco Feature Navigator, go to www.cisco.com/go/cfn . An account on Cisco.com is not required.

Prerequisites for IKE Configuration

• You should be familiar with the concepts and tasks explained in the module Configuring Security for

VPNs with IPsec .


1

Supported Standards for Use with IKE

Restrictions for IKE Configuration

• Ensure that your Access Control Lists (ACLs) are compatible with IKE. Because IKE negotiation uses

User Datagram Protocol (UDP) on port 500, your ACLs must be configured so that UDP port 500 traffic is not blocked at interfaces used by IKE and IPsec. In some cases you might need to add a statement to your ACLs to explicitly permit UDP port 500 traffic.

Restrictions for IKE Configuration

• The initiating router must not have a certificate associated with the remote peer.

• The preshared key must be by a fully qualified domain name (FQDN) on both peers. (To configure the preshared key, enter the crypto isakmp key command.)

• The communicating routers must have a FQDN host entry for each other in their configurations.

• The communicating routers must be configured to authenticate by hostname, not by IP address; thus, you should use the crypto isakmp identity hostname command.

Information About Configuring IKE for IPsec VPNs

•

Supported Standards for Use with IKE, page 2

•

IKE Benefits, page 4

•

IKE Main Mode and Aggressive Mode, page 4

•

IKE Policies Security Parameters for IKE Negotiation, page 4

•

IKE Authentication, page 5

•

IKE Mode Configuration, page 8

Supported Standards for Use with IKE

Cisco implements the following standards:

• IPsec--IP Security Protocol. IPsec is a framework of open standards that provides data confidentiality, data integrity, and data authentication between participating peers. IPsec provides these security services at the IP layer; it uses IKE to handle negotiation of protocols and algorithms based on local policy and to generate the encryption and authentication keys to be used by IPsec. IPsec can be used to protect one or more data flows between a pair of hosts, between a pair of security gateways, or between a security gateway and a host.

• ISAKMP--Internet Security Association and Key Management Protocol. A protocol framework that defines payload formats, the mechanics of implementing a key exchange protocol, and the negotiation of a security association.

• Oakley--A key exchange protocol that defines how to derive authenticated keying material.

• Skeme--A key exchange protocol that defines how to derive authenticated keying material, with rapid key refreshment.

The component technologies implemented for use by IKE include the following:

• AES--Advanced Encryption Standard. A cryptographic algorithm that protects sensitive, unclassified information. AES is privacy transform for IPsec and IKE and has been developed to replace the Data

Encryption Standard (DES). AES is designed to be more secure than DES: AES offers a larger key size, while ensuring that the only known approach to decrypt a message is for an intruder to try every

2



Information About Configuring IKE for IPsec VPNs

possible key. AES has a variable key length--the algorithm can specify a 128-bit key (the default), a

192-bit key, or a 256-bit key.

• DES--Data Encryption Standard. An algorithm that is used to encrypt packet data. IKE implements the

56-bit DES-CBC with Explicit IV standard. Cipher Block Chaining (CBC) requires an initialization vector (IV) to start encryption. The IV is explicitly given in the IPsec packet.

Cisco IOS software also implements Triple DES (168-bit) encryption, depending on the software versions available for a specific platform. Triple DES (3DES) is a strong form of encryption that allows sensitive information to be transmitted over untrusted networks. It enables customers, particularly in the finance industry, to utilize network-layer encryption.

Note

Cisco IOS images that have strong encryption (including, but not limited to, 56-bit data encryption feature sets) are subject to United States government export controls, and have a limited distribution. Images that are to be installed outside the United States require an export license. Customer orders might be denied or subject to delay because of United States government regulations. Contact your sales representative or distributor for more information, or send e-mail to [email protected].

• SEAL--Software Encryption Algorithm. An alternative algorithm to software-based DES, 3DES, and

AES. SEAL encryption uses a 160-bit encryption key and has a lower impact to the CPU when compared to other software-based algorithms.

• Diffie-Hellman--A public-key cryptography protocol that allows two parties to establish a shared secret over an unsecure communications channel. Diffie-Hellman is used within IKE to establish session keys. It supports 768-bit (the default), 1024-bit, 1536-bit, 2048-bit, 3072-bit, and 4096 DH groups and 256-bit elliptic curve DH (ECDH), Specifies the 384-bit ECDH group, and 2048-bit

DH/DSA group.

• MD5--Message Digest 5 (Hash-Based Message Authentication Code (HMAC) variant). A hash algorithm used to authenticate packet data. HMAC is a variant that provides an additional level of hashing.

• SHA-2 and SHA-1 family (HMAC variant)--Secure Hash Algorithm (SHA) 1 and 2. Both SHA-1 and

SHA-2 are hash algorithms used to authenticate packet data and verify the integrity verification mechanisms for the IKE protocol. HMAC is a variant that provides an additional level of hashing.

SHA-2 family adds the SHA-256 bit hash algorithm and SHA-384 bit hash algorithm. This functionality is part of the Suite-B requirements that comprise of four user interface suites of cryptographic algorithms for use with IKE and IPSec that are described in RFC 4869. Each suite consists of an encryption algorithm, a digital signature algorithm, a key agreement algorithm, and a hash or message digest algorithm. See the Configuring Security for VPNs with IPsec feature module for more detailed information about Cisco IOS Suite-B support.

• RSA signatures and RSA encrypted nonces--RSA is the public key cryptographic system developed by

Ron Rivest, Adi Shamir, and Leonard Adleman. RSA signatures provide nonrepudiation, and RSA encrypted nonces provide repudiation. (Repudation and nonrepudation have to do with traceability.)

IKE interoperates with the X.509v3 certificates, which are used with the IKE protocol when authentication requires public keys. This certificate support allows the protected network to scale by providing the equivalent of a digital ID card to each device. When two devices intend to communicate, they exchange digital certificates to prove their identity (thus removing the need to manually exchange public keys with each peer or to manually specify a shared key at each peer).


3

IKE Benefits

About IKE Policies

IKE Benefits

IKE automatically negotiates IPsec security associations (SAs) and enables IPsec secure communications without costly manual preconfiguration. Specifically, IKE provides the following benefits:

• Eliminates the need to manually specify all the IPsec security parameters in the crypto maps at both peers.

• Allows you to specify a lifetime for the IPsec SA.

• Allows encryption keys to change during IPsec sessions.

• Allows IPsec to provide antireplay services.

• Permits certification authority (CA) support for a manageable, scalable IPsec implementation.

• Allows dynamic authentication of peers.

IKE Main Mode and Aggressive Mode

IKE has two phases of key negotiation: phase 1 and phase 2. Phase 1 negotiates a security association (a key) between two IKE peers. The key negotiated in phase 1 enables IKE peers to communicate securely in phase 2. During phase 2 negotiation, IKE establishes keys (security associations) for other applications, such as IPsec.

Phase 1 negotiation can occur using main mode or aggressive mode. Main mode tries to protect all information during the negotiation, meaning that no information is available to a potential attacker. When main mode is used, the identities of the two IKE peers are hidden. Although this mode of operation is very secure, it is relatively costly in terms of the time required to complete the negotiation. Aggressive mode takes less time to negotiate keys between peers; however, it gives up some of the security provided by main mode negotiation. For example, the identities of the two parties trying to establish a security association are exposed to an eavesdropper.

The two modes serve different purposes and have different strengths. Main mode is slower than aggressive mode, but main mode is more secure and more flexible because it can offer an IKE peer more security proposals than aggressive mode. Aggressive mode is less flexible and not as secure, but much faster.

In Cisco IOS software, the two modes are not configurable. The default action for IKE authentication (rsasig, rsa-encr, or preshared) is to initiate main mode; however, in cases where there is no corresponding information to initiate authentication, and there is a preshared key associated with the hostname of the peer,

Cisco IOS software can initiate aggressive mode. Cisco IOS software will respond in aggressive mode to an

IKE peer that initiates aggressive mode.

IKE Policies Security Parameters for IKE Negotiation

An IKE policy defines a combination of security parameters to be used during the IKE negotiation. You must create an IKE policy at each peer participating in the IKE exchange.

If you do not configure any IKE policies, your router will use the default policy, which is always set to the lowest priority and which contains the default value of each parameter.

•

About IKE Policies, page 4

•

IKE Peers Agreeing Upon a Matching IKE Policy, page 5

About IKE Policies

4


IKE Authentication

IKE Peers Agreeing Upon a Matching IKE Policy

Because IKE negotiations must be protected, each IKE negotiation begins by agreement of both peers on a common (shared) IKE policy. This policy states which security parameters will be used to protect subsequent IKE negotiations and mandates how the peers are authenticated.

After the two peers agree upon a policy, the security parameters of the policy are identified by an SA established at each peer, and these SAs apply to all subsequent IKE traffic during the negotiation.

You can configure multiple, prioritized policies on each peer--e ach with a different combination of parameter values. However, at least one of these policies must contain exactly the same encryption, hash, authentication, and Diffie-Hellman parameter values as one of the policies on the remote peer. For each policy that you create, you assign a unique priority (1 through 10,000, with 1 being the highest priority).

Tip

If you are interoperating with a device that supports only one of the values for a parameter, your choice is limited to the value supported by the other device. Aside from this limitation, there is often a trade-off between security and performance, and many of these parameter values represent such a trade-off. You should evaluate the level of security risks for your network and your tolerance for these risks.

IKE Peers Agreeing Upon a Matching IKE Policy

When the IKE negotiation begins, IKE searches for an IKE policy that is the same on both peers. The peer that initiates the negotiation will send all its policies to the remote peer, and the remote peer will try to find a match. The remote peer looks for a match by comparing its own highest priority policy against the policies received from the other peer. The remote peer checks each of its policies in order of its priority

(highest priority first) until a match is found.

A match is made when both policies from the two peers contain the same encryption, hash, authentication, and Diffie-Hellman parameter values.

If a match is found, IKE will complete negotiation, and IPsec security associations will be created. If no acceptable match is found, IKE refuses negotiation and IPsec will not be established.

Note

The parameter values apply to the IKE negotiations after the IKE SA is established. Depending on the authentication method specified in a policy, additional configuration might be required (as described in the section

IKE Authentication, page 5

). If a peer’s policy does not have the required companion configuration, the peer will not submit the policy when attempting to find a matching policy with the remote peer.

IKE Authentication

IKE authentication consists of the following options and each authentication method requires additional configuration.

•

RSA Signatures, page 5

•

RSA Encrypted Nonces, page 6

•

Preshared Keys, page 6

RSA Signatures

With RSA signatures, you can configure the peers to obtain certificates from a CA. (The CA must be properly configured to issue the certificates.) Using a CA can dramatically improve the manageability and


5


RSA Encrypted Nonces

scalability of your IPsec network. Additionally, RSA signature-based authentication uses only two public key operations, whereas RSA encryption uses four public key operations, making it costlier in terms of overall performance. To properly configure CA support, see the module “Deploying RSA Keys Within a

PKI.”

The certificates are used by each peer to exchange public keys securely. (RSA signatures requires that each peer has the public signature key of the remote peer.) When both peers have valid certificates, they will automatically exchange public keys with each other as part of any IKE negotiation in which RSA signatures are used.

You can also exchange the public keys manually, as described in the section “

Configuring RSA Keys

Manually for RSA Encrypted Nonces, page 13

.”

RSA signatures provide nonrepudiation for the IKE negotiation. And, you can prove to a third party after the fact that you did indeed have an IKE negotiation with the remote peer.

RSA Encrypted Nonces

With RSA encrypted nonces, you must ensure that each peer has the public keys of the other peers.

Unlike RSA signatures, the RSA encrypted nonces method cannot use certificates to exchange public keys.

Instead, you ensure that each peer has the other’s public keys by one of the following methods:

•

Manually configuring RSA keys as described in the section “ Configuring RSA Keys Manually for

RSA Encrypted Nonces, page 13

.”

• Ensuring that an IKE exchange using RSA signatures with certificates has already occurred between the peers. (The peers’ public keys are exchanged during the RSA-signatures-based IKE negotiations if certificates are used.) To make that the IKE exchange happens, specify two policies: a higher-priority policy with RSA encrypted nonces and a lower-priority policy with RSA signatures. When IKE negotiations occur, RSA signatures will be used the first time because the peers do not yet have each other’s public keys. Then future IKE negotiations can use RSA encrypted nonces because the public keys will have been exchanged. This alternative requires that you already have CA support configured.

RSA encrypted nonces provide repudiation for the IKE negotiation; however, unlike RSA signatures, you cannot prove to a third party that you had an IKE negotiation with the remote peer.

Preshared Keys

•

Preshared Keys An Overview, page 6

•

ISAKMP Identity Setting for Preshared Keys, page 7

•

Mask Preshared Keys, page 7

•

Disable Xauth on a Specific IPsec Peer, page 7

Preshared Keys An Overview

Preshared keys are clumsy to use if your secured network is large, and they do not scale well with a growing network. However, they do not require use of a CA, as do RSA signatures, and might be easier to set up in a small network with fewer than ten nodes. RSA signatures also can be considered more secure when compared with preshared key authentication.

6



ISAKMP Identity Setting for Preshared Keys

Note

If RSA encryption is configured and signature mode is negotiated (and certificates are used for signature mode), the peer will request both signature and encryption keys. Basically, the router will request as many keys as the configuration will support. If RSA encryption is not configured, it will just request a signature key.

ISAKMP Identity Setting for Preshared Keys

You should set the ISAKMP identity for each peer that uses preshared keys in an IKE policy.

When two peers use IKE to establish IPsec SAs, each peer sends its identity to the remote peer. Each peer sends either its hostname or its IP address, depending on how you have set the ISAKMP identity of the router.

By default, a peer’s ISAKMP identity is the IP address of the peer. If appropriate, you could change the identity to be the peer's hostname instead. As a general rule, set the identities of all peers the same way-either all peers should use their IP addresses or all peers should use their hostnames. If some peers use their hostnames and some peers use their IP addresses to identify themselves to each other, IKE negotiations could fail if the identity of a remote peer is not recognized and a Domain Name System (DNS) lookup is unable to resolve the identity.

Mask Preshared Keys

A mask preshared key allows a group of remote users with the same level of authentication to share an IKE preshared key. The preshared key of the remote peer must match the preshared key of the local peer for

IKE authentication to occur.

A m ask preshared key is usually distributed through a secure out-of-band channel. In a remote peer-tolocal peer scenario, any remote peer with the IKE preshared key configured can establish IKE SAs with the local peer.

If you specify the mask keyword with the crypto isakmp key command, it is up to you to use a subnet address, which will allow more peers to share the same key. That is, the preshared key is no longer restricted to use between two users.

Note

Using 0.0.0.0 as a subnet address is not recommended because it encourages group preshared keys, which allow all peers to have the same group key, thereby reducing the security of your user authentication.

Disable Xauth on a Specific IPsec Peer

Disabling Extended Authentication (Xauth) for static IPsec peers prevents the routers from being prompted for Xauth information--username and password.

Without the ability to disable Xauth, a user cannot select which peer on the same crypto map should use

Xauth. That is, if a user has router-to-router IPsec on the same crypto map as a VPN-client-to-Cisco-IOS

IPsec, both peers are prompted for a username and password. In addition, a remote static peer (a Cisco IOS router) cannot establish an IKE SA with the local Cisco IOS router. (Xauth is not an optional exchange, so if a peer does not respond to an Xauth request, the IKE SA is deleted.) Thus, the same interface cannot be used to terminate IPsec to VPN clients (that need Xauth) and to other Cisco IOS routers (that cannot respond to Xauth) unless this feature is implemented.


7

IKE Mode Configuration

How to Configure IKE for IPsec VPNs

Note

Xauth can be disabled only if preshared keys are used as the authentication mechanism for the given crypto map.

IKE Mode Configuration

IKE mode configuration, as defined by the Internet Engineering Task Force (IETF), allows a gateway to download an IP address (and other network-level configuration) to the client as part of an IKE negotiation.

Using this exchange, the gateway gives an IP address to the IKE client to be used as an “inner” IP address encapsulated under IPsec. This method provides a known IP address for the client that can be matched against IPsec policy.

To implement IPsec VPNs between remote access clients that have dynamic IP addresses and a corporate gateway, you have to dynamically administer scalable IPsec policy on the gateway once each client is authenticated. With IKE mode configuration, the gateway can set up a scalable policy for a very large set of clients regardless of the IP addresses of those clients.

There are two types of IKE mode configuration:

• Gateway initiation--Gateway initiates the configuration mode with the client. Once the client responds, the IKE modifies the identity of the sender, the message is processed, and the client receives a response.

• Client initiation--Client initiates the configuration mode with the gateway. The gateway responds with an IP address that it has allocated for the client.


If you do not want IKE to be used with your IPsec implementation, you can disable it at all IPsec peers via the no crypto isakmp command, skip the rest of this chapter, and begin your IPsec VPN.

Note

If you disable IKE, you will have to manually specify all the IPsec SAs in the crypto maps at all peers, the

IPsec SAs of the peers will never time out for a given IPsec session, the encryption keys will never change during IPsec sessions between the peers, anti-replay services will not be available between the peers, and public key infrastructure (PKI) support cannot be used.

IKE is enabled by default. IKE does not have to be enabled for individual interfaces, but it is enabled globally for all interfaces at the router.

Perform the following tasks to provide authentication of IPsec peers, negotiate IPsec SAs, and establish

IPsec keys:

•

Creating IKE Policies, page 8

•

Configuring IKE Authentication, page 13

•

Configuring IKE Mode Configuration, page 20

•

Configuring an IKE Crypto Map for IPsec SA Negotiation, page 21

Creating IKE Policies

Perform this task to create an IKE policy.

8




Note

If you are configuring an AES IKE policy, note the following restrictions:

• Your router must support IPsec and long keys (the “k9” subsystem).

• AES cannot encrypt IPsec and IKE traffic if an acceleration card is present.

SUMMARY STEPS

1. enable

2. configure terminal

3. crypto isakmp policy priority

4. encryption {des | 3des | aes | aes 192 | aes 256}

5. hash {sha | sha256 | sha384 | md5}

6. authentication {rsa-sig | rsa-encr | pre-share}

7. group {1 | 2 | 5 | 14 | 15 | 16 | 19 | 20 | 24}

8. lifetime seconds

9. exit

10. exit

11. show crypto isakmp policy

12. Repeat these steps for each policy you want to create.

DETAILED STEPS

Command or Action

Step 1 enable

Purpose

Enables privileged EXEC mode.

• Enter your password if prompted.

Example:

Router> enable

Step 2 configure terminal

Enters global configuration mode.

Example:

Router# configure terminal

Step 3 crypto isakmp policy priority

Example:

Router(config)# crypto isakmp policy 10

Defines an IKE policy and enters config-isakmp configuration mode.

• priority --Uniquely identifies the IKE policy and assigns a priority to the policy. Valid values: 1 to 10,000; 1 is the highest priority.


9




Step 4 encryption {des | 3des | aes | aes 192 |

aes 256}

Example:

Router(config-isakmp)# encryption aes 256

Purpose

Specifies the encryption algorithm.

• By default, the des keyword is used.

◦ des--56-bit DES-CBC

◦ 3des--168-bit DES

◦ aes--128-bit AES

◦ aes 192--192-bit AES

◦ aes 256--256-bit AES

Step 5 hash {sha | sha256 | sha384 | md5}

Example:

Router(config-isakmp)# hash sha

Specifies the hash algorithm.

• By default, SHA-1 (sha) is used.

• The sha256 keyword specifies SHA-2 family 256-bit (HMAC variant) as the hash algorithm.

• The sha384 keyword specifies SHA-2 family 384-bit (HMAC variant) as the hash algorithm.

• The md5 keyword specifies MD5 (HMAC variant) as the hash algorithm.

Note

MD5 has a smaller digest and is considered to be slightly faster than

SHA-1.

Step 6 authentication {rsa-sig | rsa-encr |

pre-share}

Example:

Router(config-isakmp)# authentication pre-share

Specifies the authentication method.

• By default, RSA signatures are used.

◦ rsa-sig--RSA signatures require that you configure your peer routers

to obtain certificates from a CA.

◦ rsa-encr--RSA encrypted nonces require that you ensure each peer

has the other peer’s RSA public keys.

◦ pre-share--Preshared keys require that you separately configure

these preshared keys.

10





Step 7 group {1 | 2 | 5 | 14 | 15 | 16 | 19 | 20 |

24}

Example:

Router(config-isakmp)# group 1

Step 8 lifetime seconds

Example:

Router(config-isakmp)# lifetime

180

Step 9 exit

Purpose

Specifies the Diffie-Hellman (DH) group identifier.

• By default, DH group 1 is used.

◦ 1--768-bit DH

◦ 2--1024-bit DH

◦ 5--1536-bit DH

◦ 14--Specifies the 2048-bit DH group.



◦ 19--Specifies the 256-bit elliptic curve DH (ECDH) group.

◦ 20--Specifies the 384-bit ECDH group.

◦ 24--Specifies the 2048-bit DH/DSA group.

The group chosen must be strong enough (have enough bits) to protect the

IPsec keys during negotiation. A generally accepted guideline recommends the use of a 2048-bit group after 2013 (until 2030). Either group 14 or group 24 can be selected to meet this guideline. Even if a longer-lived security method is needed, the use of Elliptic Curve Cryptography is recommended, but group 15 and group 16 can also be considered.

The ISAKMP group and the IPsec perfect forward secrecy (PFS) group should be the same if PFS is used. If PFS is not used, a group is not configured in the

IPsec crypto map.

Specifies the lifetime of the IKE SA.

• seconds--Time, in seconds, before each SA expires. Valid values: 60 to

86,400; default value: 86,400.

Note

The shorter the lifetime (up to a point), the more secure your IKE negotiations will be. However, with longer lifetimes, future IPsec SAs can be set up more quickly.

Exits config-isakmp configuration mode.

Example:

Router(config-isakmp)# exit

Step 10 exit

Exits global configuration mode.

Example:

Router(config)# exit

Step 11 show crypto isakmp policy

Example:

Router# show crypto isakmp policy

(Optional) Displays all existing IKE policies.


11


Troubleshooting Tips


Step 12 Repeat these steps for each policy you want to create.

Purpose

--

Examples

The following sample output from the show crypto isakmp policy command displays a warning message after a user tries to configure an IKE encryption method that the hardware does not support:

Router# show crypto isakmp policy

Protection suite of priority 1

encryption algorithm: AES - Advanced Encryption Standard (256 bit keys).

WARNING:encryption hardware does not support the configured encryption method for ISAKMP policy 1

hash algorithm: Secure Hash Standard

authentication method: Pre-Shared Key

Diffie-Hellman group: #1 (768 bit)

lifetime: 3600 seconds, no volume limit

•

Troubleshooting Tips, page 12

•

What to Do Next, page 12


• Clear (and reinitialize) IPsec SAs by using the clear crypto sa EXEC command.

Using the clear crypto sa command without parameters will clear out the full SA database, which will clear out active security sessions. You may also specify the peer, map, or entry keywords to clear out only a subset of the SA database. For more information, see the clear crypto sa command in the Cisco IOS

Security Command Reference.

• The default policy and default values for configured policies do not show up in the configuration when you issue the show running-config command. To display the default policy and any default values within configured policies, use the show crypto isakmp policy command.

• Any IPsec transforms or IKE encryption methods that the current hardware does not support should be disabled; they are ignored whenever an attempt to negotiate with the peer is made.

If a user enters an IPsec transform or an IKE encryption method that the hardware does not support, a warning message will be generated. These warning messages are also generated at boot time. When an encrypted card is inserted, the current configuration is scanned. If any IPsec transforms or IKE encryption methods are found that are not supported by the hardware, a warning message will be generated.

What to Do Next

Depending on which authentication method you specified in your IKE policies (RSA signatures, RSA encrypted nonces, or preshared keys), you must do certain additional configuration tasks before IKE and

IPsec can successfully use the IKE policies. For information on completing these additional tasks, refer to

the Configuring IKE Authentication, page 13

.”

To configure an AES-based transform set, see the module “Configuring Security for VPNs with IPsec.”

12


Configuring IKE Authentication

Configuring RSA Keys Manually for RSA Encrypted Nonces

Configuring IKE Authentication

After you have created at least one IKE policy in which you specified an authentication method (or accepted the default method), you need to configure an authentication method. IKE policies cannot be used by IPsec until the authentication method is successfully configured.

Note

Before configuring IKE authentication, you must have configured at least one IKE policy, which is where the authentication method was specified (or RSA signatures was accepted by default).

To configure IKE authentication, you should perform one of the following tasks, as appropriate:

•

Configuring RSA Keys Manually for RSA Encrypted Nonces, page 13

•

Configuring Preshared Keys, page 17


Note

This task can be performed only if a CA is not in use.

To manually configure RSA keys, perform this task for each IPsec peer that uses RSA encrypted nonces in an IKE policy.

SUMMARY STEPS

1. enable


3. crypto key generate rsa{general-keys} | usage-keys} [label key-label] [exportable] [modulus

modulus-size]

4. crypto key generate ec keysize [256 | 384] [label label-string]

5. exit

6. show crypto key mypubkey rsa


8. crypto key pubkey-chain rsa

9. Do one of the following:

• named-key key-name [encryption | signature]

• addressed-key key-address [encryption | signature]

10. address ip-address

11. key-string key-string

12. quit

13. Repeat these steps at each peer that uses RSA encrypted nonces in an IKE policy.

14. exit

15. exit

16. show crypto key pubkey-chain rsa [name key-name | address key-address]


13



DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


Step 3 crypto key generate rsa{general-keys} | usage-

keys} [label key-label] [exportable] [modulus

modulus-size]

Generates RSA keys.

• If a key-label argument is not specified, the default value, which is the fully qualified domain name (FQDN) of the router, is used.

Example:

Router(config)# crypto key generate rsa general-keys modulus 360

Step 4 crypto key generate ec keysize [256 | 384] [label

label-string]

Example:

Router(config)# crypto key generate ec keysize 256 label Router_1_Key

Step 5 exit

Generates EC keys.

• The 256 keyword specifies a 256-bit keysize.

• The 384 keyword specifies a 384-bit keysize.

• A label can be specified for the EC key by using the label keyword and label-string argument.

Note

If a label is not specified, then FQDN value is used.

(Optional) Exits global configuration mode.

Example:


Step 6 show crypto key mypubkey rsa

Example:

Router# show crypto key mypubkey rsa


(Optional) Displays the generated RSA public keys.

Returns to global configuration mode.

Example:


14





Step 8 crypto key pubkey-chain rsa

Purpose

Enters public key chain configuration mode (so you can manually specify the RSA public keys of other devices).

Example:

Router(config)# crypto key pubkey-chain rsa

Step 9 Do one of the following:

•

named-key key-name [encryption | signature]

• addressed-key key-address [encryption |

signature]

Example:

Router(config-pubkey-chain)# named-key otherpeer.example.com

Indicates which remote peer’s RSA public key you will specify and enters public key configuration mode.

• If the remote peer uses its hostname as its ISAKMP identity, use the named-key command and specify the remote peer’s

FQDN, such as somerouter.example.com, as the key-name.

• If the remote peer uses its IP address as its ISAKMP identity, use the addressed-key command and specify the remote peer’s IP address as the key-address.

Example:

Router(config-pubkey-chain)# addressed-key

10.1.1.2 encryption

Step 10 address ip-address

Example:

Router(config-pubkey-key)# address 10.5.5.1

Specifies the IP address of the remote peer.

• If you use the named-key command, you need to use this command to specify the IP address of the peer.


15




Step 11 key-string key-string

Example:

Router(config-pubkey-key)# key-string

Example:

Router(config-pubkey)# 00302017 4A7D385B

1234EF29 335FC973

Example:

Router(config-pubkey)# 2DD50A37 C4F4B0FD

9DADE748 429618D5

Example:

Router(config-pubkey)# 18242BA3 2EDFBDD3

4296142A DDF7D3D8

Example:

Router(config-pubkey)# 08407685 2F2190A0

0B43F1BD 9A8A26DB

Example:

Router(config-pubkey)# 07953829 791FCDE9

A98420F0 6A82045B

Example:

Router(config-pubkey)# 90288A26 DBC64468

7789F76E EE21

Step 12 quit

Example:

Router(config-pubkey-key)# quit

Step 13 Repeat these steps at each peer that uses RSA encrypted nonces in an IKE policy.

Step 14 exit

Example:

Router(config-pubkey-key)# exit

Purpose

Specifies the RSA public key of the remote peer.

• (This key was previously viewed by the administrator of the remote peer when the RSA keys of the remote router were generated.)

Returns to public key chain configuration mode.

--

Returns to global configuration mode.

16



Configuring Preshared Keys


Step 15 exit

Purpose

Returns to privileged EXEC mode.

Example:


Step 16 show crypto key pubkey-chain rsa [name key-name

| address key-address]

(Optional) Displays either a list of all RSA public keys that are stored on your router or details of a particular RSA key that is stored on your router.

Example:

Router# show crypto key pubkey-chain rsa


To configure preshared keys, perform these steps for each peer that uses preshared keys in an IKE policy.

Note

Preshared keys do not scale well with a growing network. Mask preshared keys have the following restrictions:

• The SA cannot be established between the IPsec peers until all IPsec peers are configured for the same preshared key.

• The mask preshared key must be distinctly different for remote users requiring varying levels of authorization. You must configure a new preshared key for each level of trust and assign the correct keys to the correct parties. Otherwise, an untrusted party may obtain access to protected data.

SUMMARY STEPS

1. enable


3. crypto isakmp identity {address | dn | hostname}

4. ip host hostname address1 [address2...address8]


• crypto isakmp key keystring address peer-address [mask] [no-xauth]

•

crypto isakmp key keystring hostname hostname [no-xauth]


• crypto isakmp key keystring address peer-address [mask] [no-xauth]

• crypto isakmp key keystring hostname hostname [no-xauth]

7. Repeat these steps at each peer that uses preshared keys in an IKE policy.


17



DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


Step 3 crypto isakmp identity {address | dn |

hostname}

Example:

Router(config)# crypto isakmp identity address

Specifies the peer’s ISAKMP identity by IP address, by distinguished name (DN) hostname at the local peer.

• address--Typically used when only one interface (and therefore only one IP address) will be used by the peer for IKE negotiations, and the IP address is known.

• dn--Typically used if the DN of a router certificate is to be specified and chosen as the ISAKMP identity during IKE processing. The dn keyword is used only for certificate-based authentication.

• hostname--Should be used if more than one interface on the peer might be used for IKE negotiations, or if the interface’s IP address is unknown (such as with dynamically assigned IP addresses).

Step 4 ip host hostname address1 [address2...address8]

Example:

Router(config)# ip host

RemoteRouter.example.com 192.168.0.1

If the local peer’s ISAKMP identity was specified using a hostname, maps the peer’s host name to its IP address(es) at all the remote peers.

(This step might be unnecessary if the hostname or address is already mapped in a DNS server.)

18






• crypto isakmp key keystring address peer-

address [mask] [no-xauth]

• crypto isakmp key keystring hostname

hostname [no-xauth]

Example:

Router(config)# crypto isakmp key sharedkeystring address 192.168.1.33 noxauth

Example:

Router(config) crypto isakmp key sharedkeystring hostname

RemoteRouter.example.com

Purpose

Specifies at the local peer the shared key to be used with a particular remote peer.

• If the remote peer specified its ISAKMP identity with an address, use the address keyword in this step; otherwise use the

hostname keyword in this step.

◦ no-xauth--Prevents the router from prompting the peer for

Xauth information. Use this keyword if router-to-router

IPsec is on the same crypto map as VPN-client-to-Cisco IOS

IPsec.

Note

According to the design of preshared key authentication in IKE main mode, preshared keys must be based on the IP address of the peers. Although you can send a hostname as the identity of a preshared key authentication, the key is searched on the IP address of the peer; if the key is not found (based on the IP address) the negotiation will fail.


• crypto isakmp key keystring address peer-

address [mask] [no-xauth]

• crypto isakmp key keystring hostname

hostname [no-xauth]

Specifies at the remote peer the shared key to be used with the local peer.

• This is the same key you just specified at the local peer.

• If the local peer specified its ISAKMP identity with an address, use the address keyword in this step; otherwise use the

hostname keyword in this step.

Example:

Router(config) crypto isakmp key sharedkeystring address 10.0.0.1

Example:

Router(config) crypto isakmp key sharedkeystring hostname

LocalRouter.example.com

Step 7 Repeat these steps at each peer that uses preshared keys in an IKE policy.

--


19

Configuring IKE Mode Configuration


Configuring IKE Mode Configuration

Note

IKE mode configuration has the following restrictions:

• Interfaces with crypto maps that are configured for IKE mode configuration may experience a slightly longer connection setup time, which is true even for IKE peers that refuse to be configured or do not respond to the configuration mode request. In both cases, the gateway initiates the configuration of the client.

• This feature was not designed to enable the configuration mode for every IKE connection by default.

Configure this feature at the global crypto map level.

SUMMARY STEPS

1. enable


3. ip local pool pool-name start-addr end-addr

4. crypto isakmp client configuration address-pool local pool-name

5. crypto map tag client configuration address [initiate | respond]

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


Step 3 ip local pool pool-name start-addr end-addr

Defines an existing local address pool that defines a set of addresses.

Example:

Router(config)# ip local pool pool1 172.16.23.0

172.16.23.255

Step 4 crypto isakmp client configuration address-pool local pool-name

References the local address pool in the IKE configuration.

Example:

Router(config)# crypto isakmp client configuration addresspool local pool1

20


Configuring an IKE Crypto Map for IPsec SA Negotiation



Step 5 crypto map tag client configuration address [initiate | respond]

Example:

Router(config)# crypto map dyn client configuration address initiate

Purpose

Configures IKE mode configuration in global configuration mode.

Configuring an IKE Crypto Map for IPsec SA Negotiation

SUMMARY STEPS

1. enable

2. configure terminal

3. crypto map tag sequence ipsec-isakmp

4. set pfs {group1 | group2 | group5 | group14 | group15 | group16}

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable

Step 2 configure terminal


Example:


Step 3 crypto map tag sequence ipsec-

isakmp

Example:

Router(config)# crypto map example 1 ipsec-ipsec-isakmp

Specifies the crypto map and enters crypto map configuration mode.

• The tag argument specifies the crypto map.

• The sequence argument specifies the sequence to insert into the crypto map entry.

• The ipsec-isakmp keyword specifies IPsec with IKEv1 (ISAKMP).


21

Example: Creating IKE Policies

Configuration Examples for an IKE Configuration


Step 4 set pfs {group1 | group2 | group5 |

group14 | group15 | group16}

Example:

Router(config-isakmp)# set pfs

14

Purpose

Specifies the DH group identifier for IPSec SA negotiation.

• By default, DH group 1 is used.

◦ group1--768-bit DH



◦ group14--Specifies the 2048-bit DH group.



The group chosen must be strong enough (have enough bits) to protect the IPsec keys during negotiation. A generally accepted guideline recommends the use of a

2048-bit group after 2013 (until 2030). Either group 14 can be selected to meet this guideline. Even if a longer-lived security method is needed, the use of Elliptic

Curve Cryptography is recommended, but group 15 and group 16 can also be considered.

Configuration Examples for an IKE Configuration

•

Example: Creating IKE Policies, page 22

•

Example: Configuring IKE Authentication, page 24

Example: Creating IKE Policies

This section contains the following examples, which show how to configure a 3DES IKE policy and an

AES IKE policy:

•

Example: Creating 3DES IKE Policies, page 22

•

Example: Creating an AES IKE Policy, page 23

Example: Creating 3DES IKE Policies

This example creates two IKE policies, with policy 15 as the highest priority, policy 20 as the next priority, and the existing default priority as the lowest priority. It also creates a preshared key to be used with policy

20 with the remote peer whose IP address is 192.168.224.33.

crypto isakmp policy 15

encryption 3des

hash md5

authentication rsa-sig

group 2

lifetime 5000

!


authentication pre-share

lifetime 10000

!

crypto isakmp key 1234567890 address 192.168.224.33

22



Example: Creating an AES IKE Policy

In the example, the encryption DES of policy default would not appear in the written configuration because this is the default value for the encryption algorithm parameter.

If the show crypto isakmp policycommand is issued with this configuration, the output is as follows:

Protection suite priority 15 encryption algorithm:3DES - Triple Data Encryption Standard (168 bit keys) hash algorithm:Message Digest 5 authentication method:Rivest-Shamir-Adleman Signature

Diffie-Hellman group:#2 (1024 bit) lifetime:5000 seconds, no volume limit

Protection suite priority 20 encryption algorithm:DES - Data Encryption Standard (56 bit keys) hash algorithm:Secure Hash Standard authentication method:preshared Key


Default protection suite encryption algorithm:DES - Data Encryption Standard (56 bit keys) hash algorithm:Secure Hash Standard authentication method:Rivest-Shamir-Adleman Signature


Note that although the output shows “no volume limit” for the lifetimes, you can configure only a time lifetime (such as 86,400 seconds); volume-limit lifetimes are not configurable.

Example: Creating an AES IKE Policy

The following example is sample output from the show running-configcommand. In this example, the

AES 256-bit key is enabled.

Current configuration : 1665 bytes

!

version 12.2

service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption

!

hostname "Router1"

!

!

ip subnet-zero

!

!

no ip domain lookup

!

ip audit notify log ip audit po max-events 100

!


encryption aes 256


lifetime 180 crypto isakmp key cisco123 address 10.0.110.1

!

!

crypto ipsec transform-set aesset esp-aes 256 esp-sha-hmac

mode transport

!

crypto map aesmap 10 ipsec-isakmp

set peer 10.0.110.1

set transform-set aesset

match address 120

!

.

.

.


23

Example: Configuring IKE Authentication

Where to Go Next

Example: Configuring IKE Authentication

The following example shows how to manually specify the RSA public keys of two IPsec peer-- the peer at

10.5.5.1 uses general-purpose keys, and the other peer uses special-usage keys: crypto key pubkey-chain rsa

named-key otherpeer.example.com

address 10.5.5.1

key-string

005C300D 06092A86 4886F70D 01010105

00034B00 30480241 00C5E23B 55D6AB22

04AEF1BA A54028A6 9ACC01C5 129D99E4

64CAB820 847EDAD9 DF0B4E4C 73A05DD2

BD62A8A9 FA603DD2 E2A8A6F8 98F76E28

D58AD221 B583D7A4 71020301 0001

quit

exit

addressed-key 10.1.1.2 encryption

key-string

00302017 4A7D385B 1234EF29 335FC973

2DD50A37 C4F4B0FD 9DADE748 429618D5

18242BA3 2EDFBDD3 4296142A DDF7D3D8

08407685 2F2190A0 0B43F1BD 9A8A26DB

07953829 791FCDE9 A98420F0 6A82045B

90288A26 DBC64468 7789F76E EE21

quit

exit

addressed-key 10.1.1.2 signature

key-string

0738BC7A 2BC3E9F0 679B00FE 53987BCC

01030201 42DD06AF E228D24C 458AD228

58BB5DDD F4836401 2A2D7163 219F882E

64CE69D4 B583748A 241BED0F 6E7F2F16

0DE0986E DF02031F 4B0B0912 F68200C4

C625C389 0BFF3321 A2598935 C1B1

quit

exit

exit


After you have successfully configured IKE negotiation, you can begin configuring IPsec. For information on completing these tasks, see the module “Configuring Security for VPNs With IPsec.”

Additional References

Related Documents

Related Topic

Cisco IOS commands

Document Title

Cisco IOS Master Commands List, All Releases

24




Related Topic

Security commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Document Title

• Cisco IOS Security Command Reference

Commands A to C


Commands D to L


Commands M to R


Commands S to Z

IPsec configuration

IKE Version 2

Configuring Security for VPNs with IPsec

Configuring Internet Key Exchange Version 2 and

FlexVPN

Configuring RSA keys to obtain certificates from a

CA

Deploying RSA Keys Within a PKI

Suite-B ESP transforms

Suite-B Integrity algorithm type transform configuration.



FlexVPN

Suite-B Elliptic curve Diffie-Hellman (ECDH) support for IPsec SA negotiation


FlexVPN

Suite-B support for certificate enrollment for a PKI Configuring Certificate Enrollment for a PKI

Standards

Standards

None

Title

--

MIBs

MIBs

None

MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS software releases, and feature sets, use Cisco MIB Locator found at the following

URL: http://www.cisco.com/go/mibs

RFCs

RFCs

RFC 2408

Title

Internet Security Association and Key Management

Protocol (ISAKMP)


25


Feature Information for Configuring IKE for IPsec VPNs

RFCs

RFC 2409

RFC 2412

Title

The Internet Key Exchange (IKE)

The OAKLEY Key Determination Protocol

Technical Assistance

Description

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with

Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Link

http://www.cisco.com/cisco/web/support/ index.html

Feature Information for Configuring IKE for IPsec VPNs

The following table provides release information about the feature or features described in this module.

This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.



Table 1 Feature Information for Configuring IKE for IPsec VPNs

Feature Name

Ability to Disable Extended

Authentication for Static IPsec

Peers

Releases

12.2(4)T

Feature Information

This feature allows a user to disable Xauth while configuring the preshared key for router-torouter IPsec. Thus, the router will not prompt the peer for a username and password, which are transmitted when Xauth occurs for VPN-client-to-Cisco-

IOS IPsec.

The following command was modified by this feature: crypto

isakmp key.

26



Feature Name

Advanced Encryption Standard

(AES)

SEAL Encryption

Suite-B support in IOS SW crypto

Releases

12.2(8)T

12.3(7)T

15.1(2)T


This feature adds support for the new encryption standard AES, which is a privacy transform for

IPsec and IKE and has been developed to replace DES.

The following commands were modified by this feature: crypto

ipsec transform-set, encryption

(IKE policy), show crypto ipsec

transform-set, crypto ipsec

transform-set, show crypto

isakmp policy.

This feature adds support for

SEAL encryption in IPsec.

The following command was modified by this feature: crypto

ipsec transform-set.

Suite-B adds support in the Cisco

IOS for the SHA-2 family

(HMAC variant) hash algorithm used to authenticate packet data and verify the integrity verification mechanisms for the

IKE protocol. HMAC is a variant that provides an additional level of hashing. This feature also adds elliptic curve Diffie-Hellman

(ECDH) support for IPsec SA negotiation.

See the Configuring Security for

VPNs with IPsec feature module for more detailed information about Cisco IOS Suite-B support.

The following command was modified by this feature:

authentication, crypto key generate ec keysize, crypto map, group, hash, set pfs.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S.

and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks .

Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)


27


Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

28



The Call Admission Control for IKE feature describes the application of Call Admission Control (CAC) to the Internet Key Exchange (IKE) protocol in Cisco IOS software. CAC limits the number of simultaneous IKE and IPsec security associations (SAs) that is, calls to CAC that a router can establish.

•


•

Prerequisites for Call Admission Control for IKE, page 29

•

Information About Call Admission Control for IKE, page 29

•

How to Configure Call Admission Control for IKE, page 31

•

Configuration Examples for Call Admission Control for IKE, page 34

•


•

Feature Information for Call Admission Control for IKE, page 35





Prerequisites for Call Admission Control for IKE

• Configure IKE on the router.

Information About Call Admission Control for IKE

•

IKE Session, page 30

•

Security Association Limit, page 30

•

Limit on Number of In-Negotiation IKE Connections, page 30

•

System Resource Usage, page 30


29

IKE Session

Information About Call Admission Control for IKE

IKE Session

There are two ways to limit the number of IKE SAs that a router can establish to or from another router:

• Configure the absolute IKE SA limit by entering the crypto call admission limit command. The router drops new IKE SA requests when the value has been reached.

• Configure the system resource limit by entering the call admission limit command. The router drops new IKE SA requests when the level of system resources that are configured in the unit of charge is being used.

CAC is applied only to new SAs (that is, when an SA does not already exist between the peers). Every effort is made to preserve existing SAs. Only new SA requests will ever be denied due to a lack of system resources or because the configured IKE SA limit has been reached.

Security Association Limit

An SA is a description of how two or more entities will utilize security services to communicate securely on behalf of a particular data flow. IKE requires and uses SAs to identify the parameters of its connections.

IKE can negotiate and establish its own SA. An IKE SA is used by IKE only, and it is bidirectional. An

IKE SA cannot limit IPsec.

IKE drops SA requests based on a user-configured SA limit. To configure an IKE SA limit, enter the

crypto call admission limit command. When there is a new SA request from a peer router, IKE determines whether the number of active IKE SAs plus the number of SAs being negotiated meets or exceeds the configured SA limit. If the number is greater than or equal to the limit, the new SA request is rejected and a syslog is generated. This log contains the source destination IP address of the SA request.

The ipsec sa number and ike sa number keyword and argument pairs in the crypto call admission

limitcommand set the limit for the number of established IPsec SAs and IKE SAs.

Limit on Number of In-Negotiation IKE Connections

Effective with Cisco IOS Release 12.4(6)T, a limit on the number of in-negotiation IKE connections can be configured. This type of IKE connection represents either an aggressive mode IKE SA or a main mode IKE

SA prior to its authentication and actual establishment.

Using the crypto call admission limit ike in-negotiation-sa number command allows the configured number of in-negotiation IKE SAs to start negotiation without contributing to the maximum number of IKE

SAs allowed.

The all in-negotiation-sa number and ike in-negotiation-sa number keyword and argument pairs in the

crypto call admission limit command limit all the SAs in negotiation and IKE SAs in negotiation.

System Resource Usage

CAC polls a global resource monitor so that IKE knows when the router is running short of CPU cycles or memory buffers. You can configure a limit, in the range 1 to 100000, that represents the level of system resource usage in system resource usage units. When that level of resources is being used, IKE drops (will not accept new) SA requests. To configure the system resource usage limit, enter the call admission limit command.

For each incoming new SA request, the current load on the router is converted into a numerical value, representing the system resource usage level, and is compared to the resource limit set by the call

30


Configuring the IKE Security Association Limit

How to Configure Call Admission Control for IKE

admission limit command. If the current load is more than the configured resource limit, IKE drops the new SA request. Load on the router includes active SAs, CPU usage, and SA requests being considered.

The call admission load command configures a multiplier value from 0 to 1000 that represents a scaling factor for current system resource usage and a load metric poll rate of 1 to 32 seconds. The numerical value for the system resource usage level is calculated by the formula (scaling factor * current system resource usage) / 100. It is recommended that the call admission load command not be used unless advised by a

Cisco Technical Assistance Center (TAC) engineer.


•

Configuring the IKE Security Association Limit, page 31

•

Configuring the System Resource Limit, page 32

•

Verifying the Call Admission Control for IKE Configuration, page 33

Configuring the IKE Security Association Limit

Perform this task to configure the absolute IKE SA limit. The router drops new IKE SA requests when the limit has been reached.

SUMMARY STEPS

1. enable


3. crypto call admission limit {all in-negotiation-sa number | ipsec sa number | ike {in-negotiation-sa

number | sa number}}

4. exit

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:



31

Configuring the System Resource Limit



Step 3 crypto call admission limit {all in-negotiation-sa number |

ipsec sa number | ike {in-negotiation-sa number | sa

number}}

Purpose

Specifies the maximum number of IKE SAs or total SAs in negotiation or the maximum IKE SAs or IPsec SAs that can be established before IKE begins rejecting new

SA requests.

Example:

Router(config)# crypto call admission limit ike sa

25

Step 4 exit

Exits global configuration mode and returns to privileged

EXEC mode.

Example:


Configuring the System Resource Limit

Perform this task to configure the system resource limit. The router drops new IKE SA requests when the level of system resources that are configured in the unit of charge is being used.

SUMMARY STEPS

1. enable


3. call admission limit charge

4. exit

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


32


Verifying the Call Admission Control for IKE Configuration



Step 3 call admission limit charge

Purpose

Sets the level of the system resources that, when used, causes IKE to stop accepting new SA requests.

• charge --Valid values are 1 to 100000.

Example:

Router(config)# call admission limit 1000

Step 4 exit

Exits global configuration mode and returns to privileged EXEC mode.

Example:


Verifying the Call Admission Control for IKE Configuration

To verify the CAC for IKE configuration, perform the following steps.

SUMMARY STEPS

1. show call admission statistics

2. show crypto call admission statistics

DETAILED STEPS

Step 1

show call admission statistics

Use this command to monitor the global CAC configuration parameters and the behavior of CAC.

Step 2

Example:

Router# show call admission statistics

Total Call admission charges: 82, limit 1000

Total calls rejected 1430, accepted 0

Load metric: charge 82, unscaled 82%

show crypto call admission statistics

Use this command to monitor crypto CAC statistics.

Example:

Router# show crypto call admission statistics

---------------------------------------------------------------------

Crypto Call Admission Control Statistics

---------------------------------------------------------------------

System Resource Limit: 111 Max IKE SAs: 0 Max in nego: 1000

Total IKE SA Count: 0 active: 0 negotiating: 0

Incoming IKE Requests: 0 accepted: 0 rejected: 0

Outgoing IKE Requests: 0 accepted: 0 rejected: 0

Rejected IKE Requests: 0 rsrc low: 0 Active SA limit: 0

In-neg SA limit: 0

IKE packets dropped at dispatch: 0

Max IPSEC SAs: 111


33

Example Configuring the IKE Security Association Limit

Configuration Examples for Call Admission Control for IKE

Total IPSEC SA Count: 0 active: 0 negotiating: 0

Incoming IPSEC Requests: 0 accepted: 0 rejected: 0

Outgoing IPSEC Requests: 0 accepted: 0 rejected: 0

Phase1.5 SAs under negotiation: 0

Configuration Examples for Call Admission Control for IKE

•

Example Configuring the IKE Security Association Limit, page 34

•

Example Configuring the System Resource Limit, page 34

Example Configuring the IKE Security Association Limit

The following example shows how to specify a maximum limit of 25 SAs before IKE starts rejecting new

SA requests:

Router(config)# crypto call admission limit ike sa 25

Example Configuring the System Resource Limit

The following example shows how to specify that IKE should drop SA requests when the level of system resources that are configured in the unit of charge reaches 9000:

Router(config)# call admission limit 9000



Related Topic

Cisco IOS commands

Configuring IKE

IKE commands

Standards

Standards

None

Document Title

Cisco IOS Master Commands List, All Releases

Configuring Internet Key Exchange for IPsec VPNs

Cisco IOS Security Command Reference

Title

--

34



Feature Information for Call Admission Control for IKE

MIBs

MIBs

None

MIBs Link

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following


RFCs

RFCs

RFC 2409

Title

The Internet Key Exchange


Description



Link


Feature Information for Call Admission Control for IKE






35


Table 2 Feature Information for Call Admission Control for IKE

Feature Name Releases Feature Information

Call Admission Control for IKE 12.3(8)T 12.2(18)SXD1 12.4(6)T

12.2(33)SRA 12.2(33)SXH

The Call Admission Control for

IKE feature describes the application of Call Admission

Control (CAC) to the Internet

Key Exchange (IKE) protocol in

Cisco IOS software.

In Cisco IOS Release 12.3(8)T, this feature was introduced.

This feature was integrated into

Cisco IOS Release 12.2(18)SXD1 and implemented on the Cisco

6500 and Cisco 7600 routers.

In Cisco IOS Release 12.4(6)T, the ability to configure a limit on the number of in-negotiation IKE connections was added.

The following sections provide information about this feature:

The following commands were introduced or modified: call

admission limit, clear crypto

call admission statistics, crypto

call admission limit, show call

admission statistics, show

crypto call admission statistics.

IKEv1 Hardening 15.1(3)T The IKEv1 hardening feature describes the enhancements made to the Call Admission Control

(CAC) for IKE feature.



The following commands were introduced or modified: crypto

call admission limit, show

crypto call admission statistics.



36






37

Example Configuring the System Resource Limit

38



The Certificate to ISAKMP Profile Mapping feature enables you to assign an Internet Security

Association and Key Management Protocol (ISAKMP) profile to a peer on the basis of the contents of arbitrary fields in the certificate. In addition, this feature allows you to assign a group name to those peers that are assigned an ISAKMP profile.

•


•

Prerequisites for Certificate to ISAKMP Profile Mapping, page 39

•

Restrictions for Certificate to ISAKMP Profile Mapping, page 39

•

Information About Certificate to ISAKMP Profile Mapping, page 40

•

How to Configure Certificate to ISAKMP Profile Mapping, page 41

•

Configuration Examples for Certificate to ISAKMP Profile Mapping, page 44

•


•

Feature Information for Certificate to ISAKMP Profile Mapping, page 48





Prerequisites for Certificate to ISAKMP Profile Mapping

• You should be familiar with configuring certificate maps.

• You should be familiar with configuring ISAKMP profiles.

Restrictions for Certificate to ISAKMP Profile Mapping

This feature is not applicable if you use Rivest, Shamir, and Adelman (RSA)-signature or RSA-encryption authentication without certificate exchange. ISAKMP peers must be configured for RSA-signature or RSAencryption authentication using certificates.

IPsec with two trustpoints enrolled in the same Certificate Authority (CA) server is not supported. When there are two or more ISAKMP profiles, each having a different trustpoint enrolled in the same CA server,


39

Certificate to ISAKMP Profile Mapping Overview

Information About Certificate to ISAKMP Profile Mapping

the responder selects the last global trustpoint. (Trustpoints are selected in the reverse order in which they are defined globally). For the IPsec tunnel establishment to be successful for peers, the trustpoint selected by the initiator should match the trustpoint selected by the responder. All other IPsec tunnels will fail to establish connection if the trustpoints do not match.

Information About Certificate to ISAKMP Profile Mapping

•

Certificate to ISAKMP Profile Mapping Overview, page 40

•

How Certificate to ISAKMP Profile Mapping Works, page 40

•

Assigning an ISAKMP Profile and Group Name to a Peer, page 41

Certificate to ISAKMP Profile Mapping Overview

Prior to Cisco IOS Release 12.3(8)T, the only way to map a peer to an ISAKMP profile was as follows.

The ISAKMP identity field in the ISAKMP exchange was used for mapping a peer to an ISAKMP profile.

When certificates were used for authentication, the ISAKMP identity payload contained the subject name from the certificate. If a CA did not provide the required group value in the first Organizational Unit (OU) field of a certificate, an ISAKMP profile could not be assigned to a peer.

Effective with Cisco IOS Release 12.3(8)T, a peer can still be mapped as explained above. However, the

Certificate to ISAKMP Profile Mapping feature enables you to assign an ISAKMP profile to a peer on the basis of the contents of arbitrary fields in the certificate. You are no longer limited to assigning an

ISAKMP profile on the basis of the subject name of the certificate. In addition, this feature allows you to assign a group to a peer to which an ISAKMP profile has been assigned.

How Certificate to ISAKMP Profile Mapping Works

The figure below illustrates how certificate maps may be attached to ISAKMP profiles and assigned group names.

Figure 1 Certificate Maps Mapped for Profile Group Assignment

40


Assigning an ISAKMP Profile and Group Name to a Peer

How to Configure Certificate to ISAKMP Profile Mapping

A certificate map can be attached to only one ISAKMP profile although an ISAKMP profile can have several certificate maps attached to it.

Certificate maps provide the ability for a certificate to be matched with a given set of criteria. ISAKMP profiles can bind themselves to certificate maps, and if the presented certificate matches the certificate map present in an ISAKMP profile, the peer will be assigned the ISAKMP profile. If the ISAKMP profile contains a client configuration group name, the same group name will be assigned to the peer. This

ISAKMP profile information will override the information in the ID_KEY_ID identity or in the first OU field of the certificate.

Assigning an ISAKMP Profile and Group Name to a Peer

To assign an ISAKMP profile to a peer on the basis of arbitrary fields in the certificate, use the match

certificate command after the ISAKMP profile has been defined.

To associate a group name with an ISAKMP profile that will be assigned to a peer, use the client

configuration group command, also after the ISAKMP profile has been defined.


•

Mapping the Certificate to the ISAKMP Profile, page 41

•

Verifying That the Certificate Has Been Mapped, page 42

•

Assigning the Group Name to the Peer, page 43

•

Monitoring and Maintaining Your Certificate to ISAKMP Profile Mapping, page 43

Mapping the Certificate to the ISAKMP Profile

To map the certificate to the ISAKMP profile, perform the following steps. This configuration will enable you to assign the ISAKMP profile to a peer on the basis of the contents of arbitrary fields in the certificate.

SUMMARY STEPS

1. enable


3. crypto isakmp profile profile-name

4. match certificate certificate-map

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router# enable


41

Verifying That the Certificate Has Been Mapped




Purpose


Example:


Step 3 crypto isakmp profile profile-name

Defines an ISAKMP profile and enters into crypto ISAKMP profile configuration mode.

Example:

Router (config)# crypto isakmp profile vpnprofile

Step 4 match certificate certificate-map

Accepts the name of a certificate map.

Example:

Router (conf-isa-prof)# match certificate map1

Verifying That the Certificate Has Been Mapped

The following show command may be used to verify that the subject name of the certificate map has been properly configured.

SUMMARY STEPS

1. enable

2. show crypto ca certificates

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router# enable

Step 2

show crypto ca certificates Displays information about your certificate.

Example:

Router# show crypto ca certificates

42


Assigning the Group Name to the Peer


Assigning the Group Name to the Peer

To associate a group name with a peer when the peer is mapped to an ISAKMP profile, perform the following steps.

SUMMARY STEPS

1. enable



4. client configuration group group-name

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router# enable



Example:



Defines an ISAKMP profile and enters into isakmp profile configuration mode.

Example:


Step 4 client configuration group group-name

Accepts the name of a group that will be assigned to a peer when the peer is assigned this crypto ISAKMP profile.

Example:

Router (conf-isa-prof)# client configuration group group1

Monitoring and Maintaining Your Certificate to ISAKMP Profile Mapping

To monitor and maintain your certificate to ISAKMP profile mapping, you may use the following debug command.


43

Certificates Mapped to the ISAKMP Profile on the Basis of Arbitrary Fields Example

Configuration Examples for Certificate to ISAKMP Profile Mapping

SUMMARY STEPS

1. enable

2. debug crypto isakmp

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router# enable

Step 2 debug crypto isakmp

Example:

Router# debug crypto isakmp

Displays output showing that the certificate has gone through certificate map matching and that the certificate matches the ISAKMP profile.

The command may also be used to verify that the peer has been assigned a group.

Configuration Examples for Certificate to ISAKMP Profile

Mapping

•

Certificates Mapped to the ISAKMP Profile on the Basis of Arbitrary Fields Example, page 44

•

Group Name Assigned to a Peer That Is Associated with an ISAKMP Profile Example, page 45

•

Mapping a Certificate to an ISAKMP Profile Verification Example, page 45

•

Group Name Assigned to a Peer Verification Example, page 46

Certificates Mapped to the ISAKMP Profile on the Basis of Arbitrary Fields

Example

The following configuration example shows that whenever a certificate contains “ou = green,” the

ISAKMP profile “cert_pro” will be assigned to the peer: crypto pki certificate map cert_map 10

subject-name co ou = green

!

!

crypto isakmp identity dn crypto isakmp profile cert_pro

ca trust-point 2315

ca trust-point LaBcA

initiate mode aggressive

match certificate cert_map

44


Group Name Assigned to a Peer That Is Associated with an ISAKMP Profile Example


Group Name Assigned to a Peer That Is Associated with an ISAKMP Profile

Example

The following example shows that the group “some_group” is to be associated with a peer that has been assigned an ISAKMP profile: crypto isakmp profile id_profile

ca trust-point 2315

match identity host domain cisco.com

client configuration group some_group

Mapping a Certificate to an ISAKMP Profile Verification Example

The following examples show that a certificate has been mapped to an ISAKMP profile. The examples include the configurations for the responder and initiator, show command output verifying that the subject name of the certificate map has been configured, and debug command output showing that the certificate has gone through certificate map matching and been matched to the ISAKMP profile.

Responder Configuration

crypto pki certificate map cert_map 10

! The above line is the certificate map definition.

subject-name co ou = green

! The above line shows that the subject name must have “ou = green.”

! crypto isakmp profile certpro

! The above line shows that this is the ISAKMP profile that will match if the certificate of the peer matches cert_map (shown on third line below).

ca trust-point 2315




Initiator Configuration

crypto ca trustpoint LaBcA

enrollment url http://10.76.82.20:80/cgi-bin/openscep

subject-name ou=green,c=IN

! The above line ensures that the subject name “ou = green” is set.

revocation-check none

show crypto ca certificates Command Output for the Initiator

Router# show crypto ca certificates

Certificate

Status: Available

Certificate Serial Number: 21

Certificate Usage: General Purpose

Issuer:

cn=blue-lab CA

o=CISCO

c=IN

Subject:

Name: Router1.cisco.com

c=IN

ou=green

! The above line is a double check that “ou = green” has been set as the subject name.

hostname=Router1.cisco.com

Validity Date:

start date: 14:34:30 UTC Mar 31 2004


45

Group Name Assigned to a Peer Verification Example


end date: 14:34:30 UTC Apr 1 2009

renew date: 00:00:00 UTC Jan 1 1970

Associated Trustpoints: LaBcA

debug crypto isakmp Command Output for the Responder

Router# debug crypto isakmp

6d23h: ISAKMP (0:268435460): received packet from 192.0.0.2 dport 500 sport 500 Global

(R) MM_KEY_EXCH

6d23h: ISAKMP: Main Mode packet contents (flags 1, len 892):

6d23h: ID payload

6d23h: FQDN <Router1.cisco.com> port 500 protocol 17

6d23h: CERT payload

6d23h: SIG payload

6d23h: KEEPALIVE payload

6d23h: NOTIFY payload

6d23h: ISAKMP:(0:4:HW:2):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH

6d23h: ISAKMP:(0:4:HW:2):Old State = IKE_R_MM4 New State = IKE_R_MM5

6d23h: ISAKMP:(0:4:HW:2): processing ID payload. message ID = 0

6d23h: ISAKMP (0:268435460): ID payload

next-payload : 6

type : 2

FQDN name : Router1.cisco.com

protocol : 17

port : 500

length : 28

6d23h: ISAKMP:(0:4:HW:2):: peer matches *none* of the profiles

6d23h: ISAKMP:(0:4:HW:2): processing CERT payload. message ID = 0

6d23h: ISAKMP:(0:4:HW:2): processing a CT_X509_SIGNATURE cert

6d23h: ISAKMP:(0:4:HW:2): peer's pubkey isn't cached

6d23h: ISAKMP:(0:4:HW:2): OU = green

6d23h: ISAKMP:(0:4:HW:2): certificate map matches certpro profile

! The above line shows that the certificate has gone through certificate map matching and that it matches the “certpro” profile.

6d23h: ISAKMP:(0:4:HW:2): Trying to re-validate CERT using new profile

6d23h: ISAKMP:(0:4:HW:2): Creating CERT validation list: 2315, LaBcA,

6d23h: ISAKMP:(0:4:HW:2): CERT validity confirmed.


The following configuration and debug output show that a group has been assigned to a peer.

Initiator Configuration

!

crypto isakmp profile certpro

ca trust-point 2315



client configuration group new_group

! The statement on the above line will assign the group “new_group” to any peer that matches the ISAKMP profile “certpro.”


debug crypto isakmp profile Command Output for the Responder

The following debug output example shows that the peer has been matched to the ISAKMP profile named

“certpro” and that it has been assigned a group named “new_group.”

Router# debug crypto isakmp profile

6d23h: ISAKMP (0:268435461): received packet from 192.0.0.2 dport 500 sport 500 Global

(R) MM_KEY_EXCH

6d23h: ISAKMP: Main Mode packet contents (flags 1, len 892):

6d23h: ID payload

6d23h: FQDN <Router1.cisco.com> port 500 protocol 17

46




6d23h: CERT payload

6d23h: SIG payload

6d23h: KEEPALIVE payload

6d23h: NOTIFY payload

6d23h: ISAKMP:(0:5:HW:2):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH

6d23h: ISAKMP:(0:5:HW:2):Old State = IKE_R_MM4 New State = IKE_R_MM5

6d23h: ISAKMP:(0:5:HW:2): processing ID payload. message ID = 0

6d23h: ISAKMP (0:268435461): ID payload

next-payload : 6

type : 2

FQDN name : Router1.cisco.com

protocol : 17

port : 500

length : 28

6d23h: ISAKMP:(0:5:HW:2):: peer matches *none* of the profiles

6d23h: ISAKMP:(0:5:HW:2): processing CERT payload. message ID = 0

6d23h: ISAKMP:(0:5:HW:2): processing a CT_X509_SIGNATURE cert

6d23h: ISAKMP:(0:5:HW:2): peer's pubkey isn't cached

6d23h: ISAKMP:(0:5:HW:2): OU = green

6d23h: ISAKMP:(0:5:HW:2): certificate map matches certpro profile

6d23h: ISAKMP:(0:5:HW:2): Trying to re-validate CERT using new profile

6d23h: ISAKMP:(0:5:HW:2): Creating CERT validation list: 2315, LaBcA,

6d23h: ISAKMP:(0:5:HW:2): CERT validity confirmed.

6d23h: ISAKMP:(0:5:HW:2):Profile has no keyring, aborting key search

6d23h: ISAKMP:(0:5:HW:2): Profile certpro assigned peer the group named new_group



Related Topic

Configuring ISAKMP profiles

Security commands

Standards

Standards

None

MIBs

MIBs

None

Document Title

VRF-Aware IPsec


Title

--

MIBs Link




47


Feature Information for Certificate to ISAKMP Profile Mapping

RFCs

RFC

None

Title

--


Description Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.


To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services

Newsletter, and Really Simple Syndication (RSS)

Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

Feature Information for Certificate to ISAKMP Profile

Mapping





48



Table 3 Feature Information for Certificate to ISAKMP Profile Mapping

Feature Name

Certificate to ISAKMP Profile

Mapping

Releases

12.3(8)T

12.2(33)SRA

12.2(33)SXH


The Certificate to ISAKMP

Profile Mapping feature enables you to assign an Internet Security

Association and Key

Management Protocol (ISAKMP) profile to a peer on the basis of the contents of arbitrary fields in the certificate. In addition, this feature allows you to assign a group name to those peers that are assigned an ISAKMP profile.

This feature was introduced in the

Cisco IOS Release 12.3(8)T


Cisco IOS Release 12.2(33)SRA.


Cisco IOS Release 12.2(33)SXH.






49


50



The Encrypted Preshared Key feature allows you to securely store plain text passwords in type 6

(encrypted) format in NVRAM.

Feature History for Encrypted Preshared Key

Release

12.3(2)T

Modification

This feature was introduced.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp

. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

•


•

Restrictions for Encrypted Preshared Key, page 51

•

Information About Encrypted Preshared Key, page 52

•

How to Configure an Encrypted Preshared Key, page 53

•

Configuration Examples for Encrypted Preshared Key, page 62

•

Where to Go Next, page 64

•






Restrictions for Encrypted Preshared Key

• Old ROM monitors (ROMMONs) and boot images cannot recognize the new type 6 passwords.

Therefore, errors are expected if you boot from an old ROMMON.


51

Using the Encrypted Preshared Key Feature to Securely Store Passwords

Information About Encrypted Preshared Key

• For Cisco 836 routers, please note that support for Advanced Encryption Standard (AES) is available only on IP plus images.

Information About Encrypted Preshared Key

•

Using the Encrypted Preshared Key Feature to Securely Store Passwords, page 52

•

Enabling the Encrypted Preshared Key, page 53

Using the Encrypted Preshared Key Feature to Securely Store Passwords

Using the Encrypted Preshared Key feature, you can securely store plain text passwords in type 6 format in

NVRAM using a command-line interface (CLI). Type 6 passwords are encrypted. Although the encrypted passwords can be seen or retrieved, it is difficult to decrypt them to find out the actual password. Use the

key config-key password-encryptioncommand with the password encryption aescommand to configure and enable the password (symmetric cipher AES is used to encrypt the keys). The password (key) configured using the config-key password-encryption command is the master encryption key that is used to encrypt all other keys in the router.

If you configure the password encryption aescommand without configuring the key config-key

password-encryptioncommand, the following message is printed at startup or during any nonvolatile generation (NVGEN) process, such as when the show running-config or copy running-config startup-

config commands have been configured:

“Can not encrypt password. Please configure a configuration-key with ‘key config-key’”

•

Changing a Password, page 52

•

Deleting a Password, page 52

•

Unconfiguring Password Encryption, page 53

•

Storing Passwords, page 53

•

Configuring New or Unknown Passwords, page 53

Changing a Password

If the password (master key) is changed, or reencrypted, using the key config-key password-

encryptioncommand), the list registry passes the old key and the new key to the application modules that are using type 6 encryption.

Deleting a Password

If the master key that was configured using the key config-key password-encryptioncommand is deleted from the system, a warning is printed (and a confirm prompt is issued) that states that all type 6 passwords will become useless. As a security measure, after the passwords have been encrypted, they will never be decrypted in the Cisco IOS software. However, passwords can be reencrypted as explained in the previous paragraph.

52


Enabling the Encrypted Preshared Key

Unconfiguring Password Encryption

Caution

If the password configured using the key config-key password-encryptioncommand is lost, it cannot be recovered. The password should be stored in a safe location.

Unconfiguring Password Encryption

If you later unconfigure password encryption using the no password encryption aes command, all existing type 6 passwords are left unchanged, and as long as the password (master key) that was configured using the key config-key password-encryptioncommand exists, the type 6 passwords will be decrypted as and when required by the application.

Storing Passwords

Because no one can “read” the password (configured using the key config-key password-

encryptioncommand), there is no way that the password can be retrieved from the router. Existing management stations cannot “know” what it is unless the stations are enhanced to include this key somewhere, in which case the password needs to be stored securely within the management system. If configurations are stored using TFTP, the configurations are not standalone, meaning that they cannot be loaded onto a router. Before or after the configurations are loaded onto a router, the password must be manually added (using the key config-key password-encryptioncommand). The password can be manually added to the stored configuration but is not recommended because adding the password manually allows anyone to decrypt all passwords in that configuration.

Configuring New or Unknown Passwords

If you enter or cut and paste cipher text that does not match the master key, or if there is no master key, the cipher text is accepted or saved, but an alert message is printed. The alert message is as follows:

“ciphertext>[for username bar>] is incompatible with the configured master key.”

If a new master key is configured, all the plain keys are encrypted and made type 6 keys. The existing type

6 keys are not encrypted. The existing type 6 keys are left as is.

If the old master key is lost or unknown, you have the option of deleting the master key using the no key

config-key password-encryptioncommand. Deleting the master key using the no key config-key

password-encryptioncommand causes the existing encrypted passwords to remain encrypted in the router configuration. The passwords will not be decrypted.

Enabling the Encrypted Preshared Key

The password encryption aes command is used to enable the encrypted password.

How to Configure an Encrypted Preshared Key

•

Configuring an Encrypted Preshared Key, page 54

•

Monitoring Encrypted Preshared Keys, page 55

•

Configuring an ISAKMP Preshared Key, page 56

•

Configuring an ISAKMP Preshared Key in ISAKMP Keyrings, page 57


53

Configuring an Encrypted Preshared Key

How to Configure an Encrypted Preshared Key

•

Configuring ISAKMP Aggressive Mode, page 58

•

Configuring a Unity Server Group Policy, page 59

•

Configuring an Easy VPN Client, page 61

Configuring an Encrypted Preshared Key

To configure an encrypted preshared key, perform the following steps.

SUMMARY STEPS

1. enable


3. key config-key password-encryption [text]

4. password encryption aes

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


Step 3 key config-key password-

encryption [text]

Example:

Router (config)# key configkey password-encryption

Step 4 password encryption aes

Stores a type 6 encryption key in private NVRAM.

• If you want to key in interactively (using the enter key) and an encrypted key already exists, you will be prompted for the following: Old key, New key, and

Confirm key.

• If you want to key in interactively but an encryption key is not present, you will be prompted for the following: New key and Confirm key.

• If you want to remove the password that is already encrypted, you will see the following prompt: “WARNING: All type 6 encrypted keys will become unusable. Continue with master key deletion? [yes/no]:”.

Enables the encrypted preshared key.

Example:

Router (config)# passwordencryption aes

•


54


Monitoring Encrypted Preshared Keys



If you see the warning message “ciphertext >[for username bar>] is incompatible with the configured master key,” you have entered or cut and pasted cipher text that does not match the master key or there is no master key. (The cipher text will be accepted or saved.) The warning message will allow you to locate the broken configuration line or lines.

Monitoring Encrypted Preshared Keys

To get logging output for encrypted preshared keys, perform the following steps.

1 enable

2

password logging

SUMMARY STEPS

1. enable

2. password logging

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable

Step 2

password logging Provides a log of debugging output for a type 6 password operation.

Example:

Router# password logging

Examples

The following password logging debug output shows that a new master key has been configured and that the keys have been encrypted with the new master key:

Router (config)# key config-key password-encrypt

New key:

Confirm key:

Router (config)#

01:40:57: TYPE6_PASS: New Master key configured, encrypting the keys with the new master keypas

Router (config)# key config-key password-encrypt

Old key:

New key:

Confirm key:

Router (config)#

01:42:11: TYPE6_PASS: Master key change heralded, re-encrypting the keys with the new master key

01:42:11: TYPE6_PASS: Mac verification successful


55

Configuring an ISAKMP Preshared Key

What To Do Next



•

What To Do Next, page 56

What To Do Next

You can perform any of the following procedures. Each procedure is independent of the others.

Configuring an ISAKMP Preshared Key

To configure an ISAKMP preshared key, perform the following procedure.

SUMMARY STEPS

1. enable


3. crypto isakmp key keystring address peer-address

4. crypto isakmp key keystring hostname hostname

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router# enable



Example:


Step 3 crypto isakmp key keystring address peer-address

Configures a preshared authentication key.

• The peer-address argument specifies the IP address of the remote peer.

Example:

Router (config)# crypto isakmp key cisco address

10.2.3.4

Step 4 crypto isakmp key keystring hostname hostname

Configures a preshared authentication key.

Example:

• The hostname argument specifies the fully qualified domain name (FQDN) of the peer.

Router (config)# crypto isakmp key mykey hostname mydomain.com

56


Configuring an ISAKMP Preshared Key in ISAKMP Keyrings

What To Do Next

Example

The following sample output shows that an encrypted preshared key has been configured: crypto isakmp key 6 _Hg[^ÊCgLGGPF^RXTQfDDWQ][YAAB address 10.2.3.4

crypto isakmp key 6 èR\eTRaKCUZPYYQfDgXRWi_AAB hostname mydomain.com

Configuring an ISAKMP Preshared Key in ISAKMP Keyrings

To configure an ISAKMP preshared key in ISAKMP keyrings, which are used in IPSec Virtual Route

Forwarding (VRF) configurations, perform the following procedure.

SUMMARY STEPS

1. enable


3. crypto keyring keyring-name

4. pre-shared-key address address key key

5. pre-shared-key hostname hostname key key

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router# enable



Example:


Step 3 crypto keyring keyring-name

Defines a crypto keyring to be used during Internet Key

Exchange (IKE) authentication and enters keyring configuration mode.

Example:

Router (config)# crypto keyring mykeyring

Step 4 pre-shared-key address address key key

Example:

Router (config-keyring)# pre-shared-key address

10.2.3.5 key cisco

Defines a preshared key to be used for IKE authentication.

• The address argument specifies the IP address of the remote peer.


57

Configuring ISAKMP Aggressive Mode

What To Do Next


Step 5 pre-shared-key hostname hostname key key

Purpose

Defines a preshared key to be used for IKE authentication.

• The hostname argument specifies the FQDN of the peer.

Example:

Router (config-keyring)# pre-shared-key hostname mydomain.com key cisco

Example

The following show-running-config sample output shows that an encrypted preshared key in ISAKMP keyrings has been configured.

crypto keyring mykeyring

pre-shared-key address 10.2.3.5 key 6 `WHCJYR_Z]GRPF^RXTQfDcfZ]GPAAB

pre-shared-key hostname mydomain.com key 6 aE_REHDcOfYCPF^RXTQfDJYVVNSAAB

Configuring ISAKMP Aggressive Mode

To configure ISAKMP aggressive mode, perform the following steps.

SUMMARY STEPS

1. enable


3. crypto isakmp peer ip-address ip-address

4. set aggressive-mode client-endpoint client-endpoint

5. set aggressive-mode password password

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router# enable



Example:


58


Configuring a Unity Server Group Policy

What To Do Next


Step 3 crypto isakmp peer ip-address ip-address

Purpose

To enable an IP Security (IPSec) peer for IKE querying of authentication, authorization, and accounting (AAA) for tunnel attributes in aggressive mode and to enter ISAKMP peer configuration mode.

Example:

Router (config)# crypto isakmp peer ip-address

10.2.3.4

Step 4 set aggressive-mode client-endpoint client-endpoint

Specifies the Tunnel-Client-Endpoint attribute within an

ISAKMP peer configuration.

Example:

Router (config-isakmp-peer)# set aggressive-mode client-endpoint fqdn cisco.com

Step 5 set aggressive-mode password password

Specifies the Tunnel-Password attribute within an ISAKMP peer configuration.

Example:

Router (config-isakmp-peer)# set aggressive-mode password cisco

Example

The following show-running-config sample output shows that an encrypted preshared key in ISAKMP aggressive mode has been configured.

crypto isakmp peer address 10.2.3.4

set aggressive-mode password 6 âKPIQ_KJE_PPF^RXTQfDTIaLNeAAB

set aggressive-mode client-endpoint fqdn cisco.com

Configuring a Unity Server Group Policy

To configure a unity server group policy, perform the following steps.

SUMMARY STEPS

1. enable


3. crypto isakmp client configuration group group-name

4. pool name

5. domain name

6. key name


59


What To Do Next

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router# enable



Example:


Step 3 crypto isakmp client configuration group group-name

Specifies the policy profile of the group that will be defined and enters ISAKMP group configuration mode.

Example:

Router (config)# crypto isakmp client configuration group mygroup

Step 4 pool name

Defines a local pool address.

Example:

Router (config-isakmp-group)# pool mypool

Step 5 domain name

Specifies the Domain Name Service (DNS) domain to which a group belongs.

Example:

Router (config-isakmp-group)# domain cisco.com

Step 6 key name

Specifies the IKE preshared key for group policy attribute definition.

Example:

Router (config-isakmp-group)# key cisco

Example

The following show-running-config sample output shows that an encrypted key has been configured for a unity server group policy: crypto isakmp client configuration group mygroup

key 6 cZZgDZPOE\dDPF^RXTQfDTIaLNeAAB

domain cisco.com

pool mypool

60


Configuring an Easy VPN Client

What To Do Next

Configuring an Easy VPN Client

To configure an Easy VPN client, perform the following steps.

SUMMARY STEPS

1. enable


3. crypto ipsec client ezvpn name

4. peer ipaddress

5. mode client

6. group group-name key group-key

7. connect manual

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router# enable



Example:


Step 3 crypto ipsec client ezvpn name

Creates a Cisco Easy VPN remote configuration and enters Cisco

Easy VPN remote configuration mode.

Example:

Router (config)# crypto ipsec client ezvpn myclient

Step 4 peer ipaddress

Sets the peer IP address for the VPN connection.

Example:

Router (config-isakmp-peer)# peer 10.2.3.4

Step 5 mode client

Automatically configures the router for Cisco Easy VPN Client mode operation, which uses Network Address Translation (NAT) or

Peer Address Translation (PAT) address translations.

Example:

Router (config-isakmp-ezpvy)# mode client


61

Encrypted Preshared Key Example

Configuration Examples for Encrypted Preshared Key


Step 6 group group-name key group-key

Purpose

Specifies the group name and key value for the VPN connection.

Example:

Router (config-isakmp-ezvpn)# group mygroup key cisco

Step 7 connect manual

Specifies the manual setting for directing the Cisco Easy VPN remote client to wait for a command or application program interface (API) call before attempting to establish the Cisco Easy

VPN remote connection.

Example:

Router (config-isakmp-ezvpn)# connect manual

Example

The following show-running-config sample output shows that an Easy VPN client has been configured.

The key has been encrypted.

crypto ipsec client ezvpn myclient

connect manual

group mygroup key 6 gdMI`S^^[GIcPF^RXTQfDFKEO\RAAB

mode client

peer 10.2.3.4


•

Encrypted Preshared Key Example, page 62

•

No Previous Key Present Example, page 63

•

Key Already Exists Example, page 63

•

Key Already Exists But the User Wants to Key In Interactively Example, page 63

•

No Key Present But the User Wants to Key In Interactively Example, page 63

•

Removal of the Password Encryption Example, page 63

Encrypted Preshared Key Example

The following is an example of a configuration for which a type 6 preshared key has been encrypted. It includes the prompts and messages that a user might see.

Router (config)# crypto isakmp key cisco address 10.0.0.2

Router (config)# exit

Router# show running-config | include crypto isakmp key

crypto isakmp key cisco address 10.0.0.2

Router#

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router (config)# password encryption aes

Router (config)# key config-key password-encrypt

62


No Previous Key Present Example


New key:

Confirm key:

Router (config)#

01:46:40: TYPE6_PASS: New Master key configured, encrypting the keys with the new master key

Router (config)# exit

Router # show running-config | include crypto isakmp key crypto isakmp key 6 CXWdhVTZYB_Vcd^`cIHDOahiFTa address 10.0.0.2

No Previous Key Present Example

In the following configuration example, no previous key is present:

Router (config)# key config-key password-encryption testkey 123

Key Already Exists Example

In the following configuration example, a key already exists:

Router (config)# key config-key password-encryption testkey123

Old key:

Router (config)#

Key Already Exists But the User Wants to Key In Interactively Example

In the following configuration example, the user wants to key in interactively, but a key already exists. The

Old key, New key, and Confirm key prompts will show on your screen if you enter the key config-key

password-encryptioncommand and press the enter key to get into interactive mode.

Router (config)# key config-key password-encryption

Old key:

New key:

Confirm key:

No Key Present But the User Wants to Key In Interactively Example

In the following example, the user wants to key in interactively, but no key is present. The New key and

Confirm key prompts will show on your screen if you are in interactive mode.

Router (config)# key config-key password-encryption

New key:

Confirm key:

Removal of the Password Encryption Example

In the following configuration example, the user wants to remove the encrypted password. The

“WARNING: All type 6 encrypted keys will become unusable. Continue with master key deletion? [yes/ no]:” prompt will show on your screen if you are in interactive mode.

Router (config)# no key config-key password-encryption

WARNING: All type 6 encrypted keys will become unusable. Continue with master key deletion ? [yes/no]: y


63




Configure any other preshared keys.


•

Related Documents, page 64

•

Standards, page 64

•

MIBs, page 64

•

RFCs, page 64

•

Technical Assistance, page 65


Related Topic

Configuring passwords

Standards

Standards

None

MIBs

MIBs

None

RFCs

RFCs

None

Document Title


Title

--

MIBs Link



Title

--

64




Description



Link







65


66



Some third-party vendor devices, such as firewalls configured for stateful packet inspection, do not permit the passthrough of User Datagram Protocol (UDP) fragments in case they are part of a fragmentation attack. If all fragments are not passed through, Internet Key Exchange (IKE) negotiation fails because the intended responder for the virtual private network (VPN) tunnel cannot reconstruct the IKE packet and proceed with establishment of the tunnel.

This feature provides for the fragmentation of large IKE packets into a series of smaller IKE packets to avoid fragmentation at the UDP layer (for example, for large certificate payloads or certificate request payloads).

This feature provides support for Cisco IOS in terms of being a responder in an IKE main mode exchange.

•


•

Prerequisites for Fragmentation of IKE Packets, page 67

•

Restrictions for Fragmentation of IKE Packets, page 68

•

Information About Fragmentation of IKE Packets, page 68

•

How to Configure Fragmentation of IKE Packets, page 68

•

Configuration Examples for Fragmentation of IKE Packets, page 69

•


•

Feature Information for Fragmentation of IKE Packets, page 71





Prerequisites for Fragmentation of IKE Packets

• You must be using Cisco IOS software Release 12.4(15)T7 or a later release.

• The Easy VPN software client must be configured to support Network Address Translation

Transversal (NAT-T) or TCP transport for the client to send the fragmentation vendor-ID.


67


Restrictions for Fragmentation of IKE Packets

Restrictions for Fragmentation of IKE Packets

• IKE fragmentation must be proposed and supported by the initiator of the IKE exchange. You should consult documentation for Cisco Easy VPN clients to determine their capabilities for this feature.

• Do not use this feature with Cisco Easy VPN software client versions 5.01 through 5.03 because their use could lead to problems. Versions earlier than version 5.01 are not impacted, and the issue has been addressed in versions later than version 5.03.

• This feature does not support fragmentation during aggressive mode, configuration mode, or quick mode.

Information About Fragmentation of IKE Packets

The Fragmentation of IKE Packets feature provides for the fragmentation of large IKE packets into a series of smaller IKE packets to avoid fragmentation at the UDP layer (for example, for large certificate payloads or certificate request payloads).

The original IKE packet is checked for size against the minimum possible maximum transmission unit

(MTU) size of 576 bytes and split into a series of smaller fragments. Each fragment is an individual IKE packet that has its own IKE header and is afforded the same protection as negotiated at the start of the IKE exchange.

A vendor_ID indicates the capability of the initiator to support IKE fragmentation. The Cisco IOS responder, if configured to support IKE fragmentation, responds with the same vendor_ID, thus acknowledging the capability to support IKE fragmentation if required.

The vendor_IDs are exchanged in the first two main-mode exchanges so that fragmentation of packets does not occur until at least the main mode 3 (MM3) exchange.

This feature provides support for Cisco IOS in terms of being a responder in an IKE main mode exchange.

After the capabilities have been agreed upon, fragmentation occurs automatically.

If all fragments in a series are not received within the normal course of the IKE exchanges, current IKE retransmission processes are used to request that information be resent.

Note

If an IKE packet is not greater than 576 bytes in size, the packet is not fragmented.

This feature is supported for IKE via port 500, IKE via port 4500 (NAT-T), and TCP wrappers.

After configuration, the feature is enabled on the router in global configuration mode so that all incoming

IKE connection requests are possible candidates for fragmentation.

How to Configure Fragmentation of IKE Packets

To configure fragmentation of IKE packets, perform the following steps.

68



Configuration Examples for Fragmentation of IKE Packets

SUMMARY STEPS

1. enable


3. crypto isakmp fragmentation

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


Step 3 crypto isakmp fragmentation

Example:

Router (config)# crypto isakmp fragmentation

Enables fragmentation of large IKE packets into a series of smaller IKE packets to avoid fragmentation at the UDP layer.

Note

The crypto isakmp fragmentation command is only applicable when the IOS Router is acting as an Easy VPN server and the remote peer is a Cisco IPsec VPN client.

Configuration Examples for Fragmentation of IKE Packets

The following output example shows that fragmentation of IKE packets has been enabled: crypto isakmp fragmentation crypto isakmp policy 1

encryption 3des crypto isakmp profile ezvpn-SW

match group frag-clients

vrf frags


The following sections provide references related to the Fragmentation of IKE Packets feature.


69




Related Topic

Security commands

Document Title


Standards

Standard Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIB MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.



RFCs

RFC

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

Title

--







Feeds.


70



Feature Information for Fragmentation of IKE Packets

Feature Information for Fragmentation of IKE Packets





Table 4 Feature Information for Fragmentation of IKE Packets

Feature Name

Fragmentation of IKE Packets

Releases

12.4(15)T7


This feature provides for the fragmentation of large IKE packets into a series of small IKE packets to avoid fragmentation at the UDP layer.

The following command was introduced or modified: crypto

isakmp fragmentation.






71


72



The IKE Responder-Only Mode feature provides support for controlling the initiation of Internet Key

Exchange (IKE) negotiation and rekeying. When a device is configured as a responder-only device, it will not initiate IKE main, aggressive, or quick modes (for IKE and IP security [IPsec] security association

[SA] establishment) nor will it rekey IKE and IPsec SAs. The device will respond to any negotiations initiated by its peers.

•


•

Prerequisites for IKE Responder-Only Mode, page 73

•

Restrictions for IKE Responder-Only Mode, page 73

•

Information About IKE Responder-Only Mode, page 74

•

How to Configure IKE Responder-Only Mode, page 74

•

Configuration Examples for IKE Responder-Only Mode, page 75

•


•

Feature Information for IKE Responder-Only Mode, page 76





Prerequisites for IKE Responder-Only Mode

• This feature is configurable only under an IPsec profile and is relevant only to a virtual interface scenario.

Restrictions for IKE Responder-Only Mode

• Neither static nor dynamic crypto maps are supported.


73

Benefits of the IKE Responder-Only Mode Feature

Information About IKE Responder-Only Mode

Information About IKE Responder-Only Mode

•

Benefits of the IKE Responder-Only Mode Feature, page 74

Benefits of the IKE Responder-Only Mode Feature

Since the advent of virtual private network (VPN) features that allow simultaneous bidirectional IKE negotiations (with or without interesting traffic), issues with the handling and recovery of data from duplicate IKE SAs have occurred. IKE as a protocol has no ability to compare IKE negotiations to determine whether there is already an existing or in-process negotiation between two peers taking place.

These duplicate negotiations can be costly in terms of resources and confusing to router administrators.

When a device is configured as a responder-only device, it will not initiate IKE main, aggressive, or quick modes (for IKE and IPsec SA establishment), nor will it rekey IKE and IPsec SAs, thus the likelihood of duplicate SAs is reduced.

The other benefit of this feature is to allow controlled support for negotiating connections in one direction only in a load-balancing scenario. It is not recommended that the servers or hubs initiate VPN connections toward the clients or spokes because these devices are all being accessed by a single-facing IP address as advertised via the load balancer. If the hubs were to initiate the connection, they would be doing so using an individual IP address, thus circumventing the benefits of the load balancer. The same is true of rekeying requests being sourced from the hubs or servers behind the load balancer.

This feature is particularly relevant in static virtual interfaces where events such as routing protocol convergence can generate simultaneous tunnel negotiations.

How to Configure IKE Responder-Only Mode

•

Configuring a Device As IKE Responder-Only, page 74

Configuring a Device As IKE Responder-Only

To configure your device as IKE responder-only, perform the following steps.

SUMMARY STEPS

1. enable


3. crypto ipsec profile name

4. responder-only

74



Configuration Examples for IKE Responder-Only Mode

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


Step 3 crypto ipsec profile name

Defines the IPsec parameters that are to be used for IPsec encryption between two IPsec routers and enters IPsec profile configuration mode.

Example:

Router (config)# crypto ipsec profile vti

Step 4 responder-only

Configure a device as responder-only.

Example:

Router (ipsec-profile)# responder-only

Configuration Examples for IKE Responder-Only Mode

The following example shows that a device has been configured as responder-only: crypto ipsec profile vti

set transform-set 3dessha

set isakmp-profile clients

responder-only


The following sections provide references related to the IKE Responder-Only Mode feature.


Related Topic

Security commands

Document Title



75


Feature Information for IKE Responder-Only Mode

Standards

Standard Title


--

MIBs

MIB MIBs Link




RFCs

RFC

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

Title

--







Feeds.


Feature Information for IKE Responder-Only Mode



76





Table 5 Feature Information for IKE Responder-Only Mode

Feature Name

IKE Responder-Only Mode

Releases

12.4(24)T


This feature provides support for controlling the initiation of IKE negotiation and rekeying. When a device is configured as a responder-only device, it will not initiate IKE main, aggressive, or quick modes (for IKE and IPsec

SA establishment), nor will it rekey IKE and IPsec SAs. The device will respond to any negotiations initiated by its peers.

The following command was introduced: responder-only.






77

Configuring a Device As IKE Responder-Only

78



Feature History

Release

12.2(4)T

Modification

This feature was introduced.

This feature module describes the Distinguished Name Based Crypto Map feature in Cisco IOS Release

12.2(4)T. It includes the following sections:

•


•

Feature Overview, page 79

•

Supported Platforms, page 80

•

Supported Standards MIBs and RFCs, page 81

•

Prerequisites, page 81

•

Configuration Tasks, page 81

•

Configuration Examples, page 83





Feature Overview

The Distinguished Name Based Crypto Maps feature allows you to configure the router to restrict access to selected encrypted interfaces for those peers with specific certificates, especially certificates with particular

Distinguished Names (DNs).

Previously, if the router accepted a certificate or a shared secret from the encrypting peer, Cisco IOS did not have a method of preventing the peer from communicating with any encrypted interface other than the restrictions on the IP address of the encrypting peer. This feature allows you to configure which crypto maps are usable to a peer based on the DN that a peer used to authenticate itself, thereby, enabling you to control which encrypted interfaces a peer with a specified DN can access.

•

Benefits, page 80


79

Benefits

Supported Platforms

•

Restrictions, page 80

•


Benefits

The Distinguished Name Based Crypto Maps feature allows you to set restrictions in the router configuration that prevent peers with specific certificates--especially certificates with particular DNs-- from having access to selected encrypted interfaces.

Restrictions

System Requirements

To configure this feature, your router must support IP Security.

Performance Impact

If you restrict access to a large number of DNs, it is recommended that you specify a few number of crypto maps referring to large identity sections instead of specifying a large number of crypto maps referring to small identity sections.


The following documents provide information related to the Distinguished Name Based Crypto Maps feature:


• Cisco IOS Security Configuration Guide: Secure Connectivity, Release 12.4T

Supported Platforms

This feature is supported on the following platforms:

• Cisco 1700 series


• Cisco 3620

• Cisco 3640

• Cisco 3660



• Cisco uBR905 Cable Access Router

• Cisco uBR925 Cable Access Router

Determining Platform Support Through Feature Navigator



80



Supported Standards MIBs and RFCs

Supported Standards MIBs and RFCs

Standards

None

MIBs

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB

Locator found at the following URL: http://www.cisco.com/go/mibs

RFCs

None

Prerequisites

Before configuring a DN based crypto map, you must perform the following tasks:

• Create an Internet Key Exchange (IKE) policy at each peer.

For more information on creating IKE policies, refer to the “ Configuring Internet Key Exchange for IPsec

VPNs ” chapter in the Cisco IOS Security Configuration Guide: Secure Connectivity ..

• Create crypto map entries for IPSec.

For more information on creating crypto map entries, refer to the “ Configuring Security for VPNs with

IPsec ” chapter in the Cisco IOS Security Configuration Guide: Secure Connectivity

Configuration Tasks

See the following sections for configuration tasks for the Distinguished Name Based Crypto Maps feature.

Each task in the list is identified as either required or optional.

•

Configuring DN Based Crypto Maps (authenticated by DN), page 82

(required)

•

Configuring DN Based Crypto Maps (authenticated by hostname), page 82

(required)

•

Applying Identity to DN Based Crypto Maps, page 82

(required)

•

Verifying DN Based Crypto Maps, page 83

(optional)

•

Configuring DN Based Crypto Maps (authenticated by DN), page 82

•

Configuring DN Based Crypto Maps (authenticated by hostname), page 82

•

Applying Identity to DN Based Crypto Maps, page 82

•

Verifying DN Based Crypto Maps, page 83

•



81

Configuring DN Based Crypto Maps (authenticated by DN)

Configuration Tasks

Configuring DN Based Crypto Maps (authenticated by DN)

To configure a DN based crypto map that can be used only by peers that have been authenticated by a DN, use the following commands beginning in global configuration mode:

SUMMARY STEPS

1. Router(config)# crypto identity name

2. Router(crypto-identity)# dn name=string [,name=string]

DETAILED STEPS


Step 1 Router(config)# crypto identity

name

Step 2 Router(crypto-identity)# dn

name=string [,name=string]

Purpose

Configures the identity of a router with the given list of DNs in the certificate of the router and enters crypto identity configuration mode.

Associates the identity of the router with the DN in the certificate of the router.

Note

The identity of the peer must match the identity in the exchanged certificate.

Configuring DN Based Crypto Maps (authenticated by hostname)

To configure a DN based crypto map that can be used only by peers that have been authenticated by a hostname, use the following commands beginning in global configuration mode:

SUMMARY STEPS

1. Router(config)# crypto identity name

2. Router(crypto-identity)# fqdn name

DETAILED STEPS

Command or Action Purpose

Step 1 Router(config)# crypto identity

name

Configures the identity of a router with the given list of DNs in the certificate of the router and enters crypto identity configuration mode.

Step 2 Router(crypto-identity)# fqdn

name

Associates the identity of the router with the hostname that the peer used to authenticate itself.

Note

The identity of the peer must match the identity in the exchanged certificate.

Applying Identity to DN Based Crypto Maps

To apply the identity (within the crypto map context), use the following commands beginning in global configuration mode:

SUMMARY STEPS

1. Router(config)# crypto map map-name seq-num ipsec-isakmp

2. Router(config-crypto-map)# identity name

82


Verifying DN Based Crypto Maps

Configuration Examples

DETAILED STEPS

Command or Action Purpose

Step 1 Router(config)# crypto map map-

name seq-num ipsec-isakmp

Creates or modifies a crypto map entry and enters the crypto map configuration mode.

Step 2 Router(config-crypto-map)#

identity name

Applies the identity to the crypto map.

When this command is applied, only the hosts that match a configuration listed within the identity name can use the specified crypto map.

Note

If the identity command does not appear within the crypto map, the encrypted connection does not have any restrictions other than the IP address of the encrypting peer.

Verifying DN Based Crypto Maps

To verify that this functionality is properly configured, use the following command in EXEC mode:

Command Purpose

Displays the configured identities.

Router#

show crypto identity


If an encrypting peer attempts to establish a connection that is blocked by the DN based crypto map configuration, the following error message will be logged:

<time>: %CRYPTO-4-IKE_QUICKMODE_BAD_CERT: encrypted connection attempted with a peer without the configured certificate attributes.


•

DN Based Crypto Map Configuration Example, page 83

DN Based Crypto Map Configuration Example

The following example shows how to configure DN based crypto maps that have been authenticated by DN and hostname. Comments are included inline to explain various commands.

! DN based crypto maps require you to configure an IKE policy at each peer.


encryption 3des

hash md5

authentication rsa-sig

group 2

lifetime 5000 crypto isakmp policy 20


lifetime 10000 crypto isakmp key 1234567890 address 171.69.224.33


83



!

! The following is an IPSec crypto map (part of IPSec configuration). It can be used only

! by peers that have been authenticated by DN and if the certificate belongs to BigBiz.

crypto map map-to-bigbiz 10 ipsec-isakmp

set peer 172.21.114.196

set transform-set my-transformset

match address 124

identity to-bigbiz

!

crypto identity to-bigbiz

dn ou=BigBiz

!

!

! This crypto map can be used only by peers that have been authenticated by hostname

! and if the certificate belongs to little.com.

crypto map map-to-little-com 10 ipsec-isakmp

set peer 172.21.115.119

set transform-set my-transformset

match address 125

identity to-little-com

!

crypto identity to-little-com

fqdn little.com

!

84



The IPsec and Quality of Service feature allows Cisco IOS quality of service (QoS) policies to be applied to IP Security (IPsec) packet flows on the basis of a QoS group that can be added to the current Internet

Security Association and Key Management Protocol (ISAKMP) profile.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp

. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

•


•

Prerequisites for IPsec and Quality of Service, page 85

•

Restrictions for IPsec and Quality of Service, page 86

•

Information About IPsec and Quality of Service, page 86

•

How to Configure IPsec and Quality of Service, page 86

•

Configuration Examples for IPsec and Quality of Service, page 88

•


•

Feature Information for IPsec and Quality of Service, page 92





Prerequisites for IPsec and Quality of Service

• You should be familiar with IPsec and the concept of ISAKMP profiles.

• You should be familiar with Cisco IOS QoS.


85

IPsec and Quality of Service Overview

Restrictions for IPsec and Quality of Service

Restrictions for IPsec and Quality of Service

• This feature can be applied only via the ISAKMP profile. The limit of 128 QoS groups that exists for

QoS applications applies to this feature as well.

• You can apply an IPsec QoS group only to outbound service policies.

• QoS is not supported for software encryption.

Information About IPsec and Quality of Service

•

IPsec and Quality of Service Overview, page 86

IPsec and Quality of Service Overview

The IPsec and Quality of Service feature allows you to apply QoS policies, such as traffic policing and shaping, to IPsec-protected packets by adding a QoS group to ISAKMP profiles. After the QoS group has been added, this group value will be mapped to the same QoS group as defined in QoS class maps. Any current QoS method that makes use of this QoS group tag can be applied to IPsec packet flows. Common groupings of packet flows can have specific policy classes applied by having the IPsec QoS group made available to the QoS mechanism. Marking IPsec flows allows QoS mechanisms to be applied to classes of traffic that could provide support for such things as restricting the amount of bandwidth that is available to specific groups or devices or marking the type of service (ToS) bits on certain flows.

The application of the QoS group is applied at the ISAKMP profile level because it is the profile that can uniquely identify devices through its concept of match identity criteria. These criteria are on the basis of the

Internet Key Exchange (IKE) identity that is presented by incoming IKE connections and includes such things as IP address, fully qualified domain name (FQDN), and group (that is, the virtual private network

[VPN] remote client grouping). The granularity of the match identity criteria will impose the granularity of the specified QoS policy, for example, to mark all traffic belonging to the VPN client group named

“Engineering” as “TOS 5”. Another example of having the granularity of a specified QoS policy imposed would be to allocate 30 percent of the bandwidth on an outbound WAN link to a specific group of remote

VPN devices.

How to Configure IPsec and Quality of Service

•

Configuring IPsec and Quality of Service, page 86

•

Verifying IPsec and Quality of Service Sessions, page 87

•


Configuring IPsec and Quality of Service

To apply QoS policies to an ISAKMP profile, perform the following steps.

86


Verifying IPsec and Quality of Service Sessions

How to Configure IPsec and Quality of Service

SUMMARY STEPS

1. enable


3. crypto isakmp-profile profile-number

4. qos-group group-number

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


Step 3 crypto isakmp-profile profile-number

Defines an ISAKMP profile, audits IPsec user sessions, and enters ISAKMP profile configuration mode.

Example:

Router (config)# crypto isakmp-profile vpnprofile

Step 4 qos-group group-number

Applies a QoS group value to an ISAKMP profile.

Example:

Router(config-isa-prof)# qos-group 1

Verifying IPsec and Quality of Service Sessions

To verify your IPsec and QoS sessions, perform the following steps. The show commands can be used in any order or independent of each other.

SUMMARY STEPS

1. enable

2. show crypto isakmp profile

3. show crypto ipsec sa


87


Configuration Examples for IPsec and Quality of Service

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable

Step 2 show crypto isakmp profile

Shows that the QoS group is applied to the profile.

Example:

Router# show crypto isakmp profile

Step 3 show crypto ipsec sa

Shows that the QoS group is applied to a particular pair of IPsec security associations (SAs).

Example:

Router# show crypto ipsec sa


If you have a problem with your IPsec and QoS sessions, ensure that you have done the following:

• Validated the application of QoS by the QoS service using the QoS-specific commands in the Cisco

IOS Quality of Service Solutions Command Reference.

• Configured a QoS policy on the router that matches the same QoS group as that specified for the class map match criterion.

• Applied the service policy to the same interface to which a crypto map is applied.


•

QoS Policy Applied to Two Groups of Remote Users Example, page 88

•

show crypto isakmp profile Command Example, page 90

•

show crypto ipsec sa Command Example, page 90

QoS Policy Applied to Two Groups of Remote Users Example

In the following example, a specific QoS policy is applied to two groups of remote users. Two ISAKMP profiles are configured so that upon initial connection via IKE, remote users are mapped to a specific profile. From that profile, all IPsec SAs that have been created for that remote will be marked with the specific QoS group. As traffic leaves the outbound interface, the QoS service will map the IPsec set QoS

88




group with the QoS group that is specified in the class maps that comprise the service policy that is applied on that outbound interface.

version 12.3

!

aaa authentication login group group radius aaa authorization network autho local aaa accounting update periodic 1 aaa session-id common ip subnet-zero

!

!

ip cef no ip domain lookup

!

class-map match-all yellow

match qos-group 3 class-map match-all blue match qos-group 2

!

!

policy-map clients

class blue

set precedence 5

class yellow

set precedence 7

!

!


encr 3des

hash md5


group 2

lifetime 300

!

crypto isakmp keepalive 10 periodic crypto isakmp xauth timeout 20

!

crypto isakmp client configuration group blue

key cisco

dns 10.2.2.2 10.2.2.3

wins 10.6.6.6

pool blue

save-password

include-local-lan

backup-gateway corky1.cisco.com

!

crypto isakmp client configuration group yellow

dns 10.2.2.2 10.2.2.3

wins 10.6.6.5

pool yellow

!

crypto isakmp profile blue

match identity group cisco

client authentication list autho

isakmp authorization list autho

client configuration address respond

qos-group 2 crypto isakmp profile yellow

match identity group yellow

match identity address 10.0.0.11 255.255.255.255

client authentication list autho

isakmp authorization list autho


qos-group 3

!

!

crypto ipsec transform-set combo ah-sha-hmac esp-3des esp-sha-hmac crypto ipsec transform-set client esp-3des esp-sha-hmac comp-lzs

!

crypto dynamic-map mode 1

set security-association lifetime seconds 180


89

show crypto isakmp profile Command Example


set transform-set client

set isakmp-profile blue

reverse-route crypto dynamic-map mode 2

set transform-set combo

set isakmp-profile yellow

reverse-route

!

crypto map mode 1 ipsec-isakmp dynamic mode

!

interface FastEthernet0/0

ip address 10.0.0.110 255.255.255.0

no ip redirects

no ip proxy-arp

no ip mroute-cache

duplex half

no cdp enable

crypto map mode

service-policy out clients

!

ip local pool yellow 192.168.2.1 192.168.2.10

ip local pool blue 192.168.6.1 192.168.6.6

no ip classless

!

radius-server host 10.0.0.13 auth-port 1645 acct-port 1646 radius-server key XXXXXX radius-server vsa send accounting radius-server vsa send authentication

show crypto isakmp profile Command Example

The following output shows that QoS group “2” has been applied to the ISAKMP profile “blue” and that

QoS group “3” has been applied to the ISAKMP profile “yellow”:

Router# show crypto isakmp profile

ISAKMP PROFILE blue

Identities matched are:

group blue

QoS Group 2 is applied

ISAKMP PROFILE yellow

Identities matched are:

ip-address 10.0.0.13 255.255.255.255

group yellow

QoS Group 3 is applied

show crypto ipsec sa Command Example

The following output shows that the QoS group has been applied to a particular pair of IPsec SAs:

Router# show crypto ipsec sa interface: FastEthernet0/0

Crypto map tag: mode, local addr. 10.0.0.110

protected vrf:

local ident (addr/mask/prot/port): (0.0.0.0/0.0.0.0/0/0)

remote ident (addr/mask/prot/port): (10.12.12.0/255.255.255.0/0/0)

current_peer: 10.0.0.11:500

PERMIT, flags={}

#pkts encaps: 0, #pkts encrypt: 0, #pkts digest: 0

#pkts decaps: 0, #pkts decrypt: 0, #pkts verify: 0

#pkts compressed: 0, #pkts decompressed: 0

#pkts not compressed: 0, #pkts compr. failed: 0

#pkts not decompressed: 0, #pkts decompress failed: 0

#send errors 0, #recv errors 0

qos group is set to 2

90





The following sections provide references related to the IPsec and Quality of Service feature.

•


•

Standards, page 91

•

MIBs, page 91

•

RFCs, page 91

•

Technical Assistance, page 92


Related Topic

IPsec

QoS options

QoS commands

Security commands

Document Title


Cisco IOS Quality of Service Solutions

Configuration Guide on Cisco.com

Cisco IOS Quality of Service Solutions Command

Reference


Standards

Standards Title

No new or modified standards are supported by this feature.

--

MIBs

MIBs

No new or modified MIBs are supported by this feature.

MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use

Cisco MIB Locator found at the following URL: http://www.cisco.com/go/mibs

RFCs

RFCs

No new or modified RFCs are supported by this feature.

Title

--


91


Feature Information for IPsec and Quality of Service




http://www.cisco.com/techsupport



Feeds.


Feature Information for IPsec and Quality of Service





Table 6 Feature Information for IPsec and Quality of Service

Feature Name

IPsec and Quality of Service

Releases

12.3(8)T


The IPsec and Quality of Service feature allows Cisco IOS quality of service (QoS) policies to be applied to IP Security (IPsec) packet flows on the basis of a

QoS group that can be added to the current Internet Security

Association and Key

Management Protocol (ISAKMP) profile.


The following commands were introduced or modified: qos-

group.

92








93


94


VRF-Aware IPsec

The VRF-Aware IPsec feature introduces IP Security (IPsec) tunnel mapping to Multiprotocol Label

Switching (MPLS) Virtual Private Networks (VPNs). Using the VRF-Aware IPsec feature, you can map

IPsec tunnels to Virtual Routing and Forwarding (VRF) instances using a single public-facing address.

•


•

Restrictions for VRF-Aware IPsec, page 95

•

Information About VRF-Aware IPsec, page 96

•

How to Configure VRF-Aware IPsec, page 98

•

Configuration Examples for VRF-Aware IPsec, page 115

•


•

Feature Information for VRF-Aware IPsec, page 127

•

Glossary, page 128





Restrictions for VRF-Aware IPsec

• If you are configuring the VRF-Aware IPsec feature using a crypto map configuration and the Inside

VRF (IVRF) is not the same as the Front Door VRF (FVRF), this feature is not interoperable with unicast reverse path forwarding (uRPF) if uRPF is enabled on the crypto map interface. If your network requires uRPF, it is recommended that you use Virtual Tunnel Interface (VTI) for IPsec instead of crypto maps.

• The VRF-Aware IPsec feature does not allow IPsec tunnel mapping between VRFs. For example, it does not allow IPsec tunnel mapping from VRF vpn1 to VRF vpn2.

• When the VRF-Aware IPsec feature is used with a crypto map, this crypto map cannot use the global

VRF as the IVRF and a non-global VRF as the FVRF. However, configurations based on virtual tunnel interfaces do not have that limitation. When VTIs or Dynamic VTIs (DVTIs) are used, the global VRF can be used as the IVRF together with a non-global VRF used as the FVRF.


95

VRF Instance

Information About VRF-Aware IPsec

Information About VRF-Aware IPsec

•

VRF Instance, page 96

•

MPLS Distribution Protocol, page 96

•

VRF-Aware IPsec Functional Overview, page 96

VRF Instance

A VRF instance is a per-VPN routing information repository that defines the VPN membership of a customer site attached to the Provider Edge (PE) router. A VRF comprises an IP routing table, a derived

Cisco Express Forwarding (CEF) table, a set of interfaces that use the forwarding table, and a set of rules and routing protocol parameters that control the information that is included in the routing table. A separate set of routing and Cisco Express Forwarding (CEF) tables is maintained for each VPN customer.

MPLS Distribution Protocol

The MPLS distribution protocol is a high-performance packet-forwarding technology that integrates the performance and traffic management capabilities of data link layer switching with the scalability, flexibility, and performance of network-layer routing.

VRF-Aware IPsec Functional Overview

Front Door VRF (FVRF) and Inside VRF (IVRF) are central to understanding the feature.

Each IPsec tunnel is associated with two VRF domains. The outer encapsulated packet belongs to one VRF domain, which we shall call the FVRF, while the inner, protected IP packet belongs to another domain called the IVRF. Another way of stating the same thing is that the local endpoint of the IPsec tunnel belongs to the FVRF while the source and destination addresses of the inside packet belong to the IVRF.

One or more IPsec tunnels can terminate on a single interface. The FVRF of all these tunnels is the same and is set to the VRF that is configured on that interface. The IVRF of these tunnels can be different and depends on the VRF that is defined in the Internet Security Association and Key Management Protocol

(ISAKMP) profile that is attached to a crypto map entry.

96


VRF-Aware IPsec

Packet Flow into the IPsec Tunnel

The diagram below is an illustration of a scenario showing IPsec to MPLS and Layer 2 VPNs.

Figure 2 IPsec to MPLS and Layer 2 VPNs

•

Packet Flow into the IPsec Tunnel, page 97

•

Packet Flow from the IPsec Tunnel, page 97

Packet Flow into the IPsec Tunnel

• A VPN packet arrives from the Service Provider MPLS backbone network to the PE and is routed through an interface facing the Internet.

• The packet is matched against the Security Policy Database (SPD), and the packet is IPsec encapsulated. The SPD includes the IVRF and the access control list (ACL).

• The IPsec encapsulated packet is then forwarded using the FVRF routing table.

Packet Flow from the IPsec Tunnel

• An IPsec-encapsulated packet arrives at the PE router from the remote IPsec endpoint.

• IPsec performs the Security Association (SA) lookup for the Security Parameter Index (SPI), destination, and protocol.

• The packet is decapsulated using the SA and is associated with IVRF.

• The packet is further forwarded using the IVRF routing table.


97

Configuring Crypto Keyrings

How to Configure VRF-Aware IPsec


•

Configuring Crypto Keyrings, page 98

•

Configuring ISAKMP Profiles, page 100

•

Configuring an ISAKMP Profile on a Crypto Map, page 104

•

Configuring to Ignore Extended Authentication During IKE Phase 1 Negotiation, page 106

•

Verifying VRF-Aware IPsec, page 106

•

Clearing Security Associations, page 107

•

Troubleshooting VRF-Aware IPsec, page 108

Configuring Crypto Keyrings

A crypto keyring is a repository of preshared and Rivest, Shamir, and Adelman (RSA) public keys. There can be zero or more keyrings on the Cisco IOS router.

SUMMARY STEPS

1. enable


3. crypto keyring keyring-name [vrf fvrf-name]

4. description string

5. pre-shared-key {address address [mask] | hostname hostname} key key

6. rsa-pubkey {address address | name fqdn} [encryption | signature]

7. address ip-address

8. serial-number serial-number

9. key-string

10. text

11. quit

12. exit

13. exit

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable

98


VRF-Aware IPsec




Example:


Step 3 crypto keyring keyring-name [vrf fvrf-name]

Example:

Router (config)# crypto keyring VPN1

Purpose


Defines a keyring with keyring-name as the name of the keyring and enters keyring configuration mode.

• (Optional) The vrf keyword and fvrf-name argument imply that the keyring is bound to Front Door Virtual Routing and

Forwarding (FVRF). The key in the keyring is searched if the local endpoint is in FVRF. If vrf is not specified, the keyring is bound to the global.

(Optional) Specifies a one-line description of the keyring.

Step 4 description string

Example:

Example:

Router (config-keyring)# description The keys for VPN1

Step 5 pre-shared-key {address address [mask] |

hostname hostname} key key

(Optional) Defines a preshared key by address or host name.

Example:

Router (config-keyring)# pre-shared-key address 10.72.23.11 key VPN1

Step 6 rsa-pubkey {address address | name fqdn}

[encryption | signature]

Example:

Router(config-keyring)# rsa-pubkey name host.vpn.com

Step 7 address ip-address

(Optional) Defines an RSA public key by address or host name and enters rsa-pubkey configuration mode.

•

The optional encryption keyword specifies that the key should be used for encryption.

• The optional signature keyword specifies that the key should be used for signature. By default, the key is used for signature.

(Optional) Defines the RSA public key IP address.

Example:

Router(config-pubkey-key)# address 10.5.5.1


99

Configuring ISAKMP Profiles



Step 8 serial-number serial-number

Purpose

(Optional) Specifies the serial number of the public key. The value is from 0 through infinity.

Example:

Router(config-pubkey-key)# serial-number

1000000

Step 9 key-string

Enters into the text mode in which you define the public key.

Example:

Router (config-pubkey-key)# key-string

Step 10 text

Specifies the public key.

Note

Only one public key may be added in this step.

Example:

Router (config-pubkey)# 00302017 4A7D385B

1234EF29 335FC973

Step 11 quit

Quits to the public key configuration mode.

Example:

Router (config-pubkey)# quit

Step 12 exit

Example:

Router (config-pubkey)# exit

Step 13 exit

Example:

Router(config-keyring)# exit#

Exits to the keyring configuration mode.

Exits to global configuration mode.

Configuring ISAKMP Profiles

An ISAKMP profile is a repository for Internet Key Exchange (IKE) Phase 1 and IKE Phase 1.5

configuration for a set of peers. An ISAKMP profile defines items such as keepalive, trustpoints, peer identities, and XAUTH AAA list during the IKE Phase 1 and Phase 1.5 exchange. There can be zero or more ISAKMP profiles on the Cisco IOS router.

100


VRF-Aware IPsec


Note

If traffic from the router to a certification authority (CA) (for authentication, enrollment, or for obtaining a certificate revocation list [CRL]) or to an Lightweight Directory Access Protocol (LDAP) server (for obtaining a CRL) needs to be routed via a VRF, the vrfcommand must be added to the trustpoint.

Otherwise, the traffic uses the default routing table.

• If a profile does not specify one or more trustpoints, all trustpoints in the router will be used to attempt to validate the certificate of the peer (IKE main mode or signature authentication). If one or more trustpoints are specified, only those trustpoints will be used.

Note

A router initiating IKE and a router responding to the IKE request should have symmetrical trustpoint configurations. For example, a responding router (in IKE Main Mode) performing RSA signature encryption and authentication might use trustpoints that were defined in the global configuration when sending the CERT-REQ payloads. However, the router might use a restricted list of trustpoints that were defined in the ISAKMP profile for the certificate verification. If the peer (the IKE initiator) is configured to use a certificate whose trustpoint is in the global list of the responding router but not in ISAKMP profile of the responding router, the certificate will be rejected. (However, if the initiating router does not know about the trustpoints in the global configuration of the responding router, the certificate can still be authenticated.)

>

SUMMARY STEPS

1. enable



4. description string

5. vrf ivrf-name

6. keepalive seconds retry retry-seconds

7. self-identity {address | fqdn| user-fqdn user-fqdn}

8. keyring keyring-name

9. ca trust-point {trustpoint-name}

10. match identity {group group-name | address address [mask] [fvrf] | host host-name | host domain

domain-name | user user-fqdn | user domain domain-name}

11. client configuration address {initiate | respond}

12. client authentication list list-name

13. isakmp authorization list list-name

14. initiate mode aggressive

15. exit


101

VRF-Aware IPsec


DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:



Example:


Step 4 description string

Defines an Internet Security Association and Key Management Protocol

(ISAKMP) profile and enters into isakmp profile configuration mode.

(Optional) Specifies a one-line description of an ISAKMP profile.

Example:

Router (conf-isa-prof)# description configuration for VPN profile

Step 5 vrf ivrf-name

Example:

(Optional) Maps the IPsec tunnel to a Virtual Routing and Forwarding

(VRF) instance.

Note

The VRF also serves as a selector for matching the Security Policy

Database (SPD). If the VRF is not specified in the ISAKMP profile, the IVRF of the IPsec tunnel will be the same as its FVRF.

Router (conf-isa-prof)# vrf VPN1

Step 6 keepalive seconds retry retry-seconds

Example:

Router (conf-isa-prof)# keepalive

60 retry 5

(Optional) Allows the gateway to send dead peer detection (DPD) messages to the peer.

• If not defined, the gateway uses the global configured value.

• seconds --Number of seconds between DPD messages. The range is 10 to 3600 seconds.

• retry retry-seconds --Number of seconds between retries if the DPD message fails. The range is 2 to 60 seconds.

102


VRF-Aware IPsec



Step 7 self-identity {address | fqdn| user-fqdn

user-fqdn}

Example:

Router (conf-isa-prof)# selfidentity address

Step 8 keyring keyring-name

Purpose

(Optional) Specifies the identity that the local Internet Key Exchange (IKE) should use to identify itself to the remote peer.

•

•

•

• If not defined, IKE uses the global configured value.

address --Uses the IP address of the egress interface.

fqdn-- Uses the fully qualified domain name (FQDN) of the router.

user-fqdn --Uses the specified value.

(Optional) Specifies the keyring to use for Phase 1 authentication.

• If the keyring is not specified, the global key definitions are used.

Example:

Router (conf-isa-prof)# keyring VPN1

Step 9 ca trust-point {trustpoint-name}

Example:

(Optional) Specifies a trustpoint to validate a Rivest, Shamir, and Adelman

(RSA) certificate.

• If no trustpoint is specified in the ISAKMP profile, all the trustpoints that are configured on the Cisco IOS router are used to validate the certificate.

Router (conf-isa-prof)# ca trustpoint VPN1-trustpoint

Step 10 match identity {group group-name |

address address [mask] [fvrf] | host host-

name | host domain domain-name | user

user-fqdn | user domain domain-name}

Specifies the client IKE Identity (ID) that is to be matched.

Example:

Router (conf-isa-prof)# match identity address 10.1.1.1

• group group-name --Matches the group-name with the ID type

ID_KEY_ID. It also matches the group-name with the Organizational

Unit (OU) field of the Distinguished Name (DN).·

•

address address [mask] fvrf --Matches the address with the ID type

ID_IPV4_ADDR. The mask argument can be used to specify a range of addresses. The fvrf argument specifies that the address is in Front

Door Virtual Routing and Forwarding (FVRF)

• host hostname --Matches the hostname with the ID type ID_FQDN.

• host domain domain-name --Matches the domain-name to the ID type

ID_FQDN whose domain name is the same as the domain-name. Use this command to match all the hosts in the domain.

• user username --Matches the username with the ID type

ID_USER_FQDN·

• user domain domainname --Matches the ID type ID_USER_FQDN whose domain name matches the domainname.

Step 11 client configuration address {initiate |

respond}

(Optional) Specifies whether to initiate the mode configuration exchange or responds to mode configuration requests.

Example:

Router (conf-isa-prof)# client configuration address initiate


103

Configuring an ISAKMP Profile on a Crypto Map

What to Do Next


Step 12 client authentication list list-name

Purpose

(Optional) AAA (authentication, authorization, and accounting) to use for authenticating the remote client during the extended authentication

(XAUTH) exchange.

Example:

Router (conf-isa-prof)# client authentication list xauthlist

Step 13 isakmp authorization list list-name

(Optional) Network authorization server for receiving the Phase 1 preshared key and other attribute-value (AV) pairs.

Example:

Router (conf-isa-prof)# isakmp authorization list ikessaaalist

Step 14 initiate mode aggressive

(Optional) Initiates aggressive mode exchange.

• If not specified, IKE always initiates main mode exchange.

Example:

Router (conf-isa-prof)# initiate mode aggressive

Step 15 exit


Example:

Router (conf-isa-prof)# exit

•

What to Do Next, page 104

What to Do Next

Go to the section Configuring an ISAKMP Profile on a Crypto Map, page 104

.”

Configuring an ISAKMP Profile on a Crypto Map

An ISAKMP profile must be applied to the crypto map. The IVRF on the ISAKMP profile is used as a selector when matching the VPN traffic. If there is no IVRF on the ISAKMP profile, the IVRF will be equal to the FVRF. Perform this task to configure an ISAKMP profile on a crypto map.

Before configuring an ISAKMP profile on a crypto map, you must first configure your router for basic

IPsec.

104


VRF-Aware IPsec

What to Do Next

SUMMARY STEPS

1. enable


3. crypto map map-name isakmp-profile isakmp-profile-name

4. set isakmp-profile profile-name

5. exit

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


Step 3 crypto map map-name isakmp-profile isakmp-profile-

name

(Optional) Specifies the Internet Key Exchange and Key

Management Protocol (ISAKMP) profile for the crypto map set and enters crypto map configuration mode.

Example:

• The ISAKMP profile will be used during IKE exchange.

Router (config)# crypto map vpnmap isakmpprofile vpnprofile

Step 4 set isakmp-profile profile-name

(Optional) Specifies the ISAKMP profile to use when the traffic matches the crypto map entry.

Example:

Router (config-crypto-map)# set isakmpprofile vpnprofile

Step 5 exit


Example:

Router (config-crypto-map)# exit


105

Configuring to Ignore Extended Authentication During IKE Phase 1 Negotiation

What to Do Next

Configuring to Ignore Extended Authentication During IKE Phase 1

Negotiation

To ignore XAUTH during an IKE Phase 1 negotiation, use the no crypto xauth command. Use the no

crypto xauth command if you do not require extended authentication for the Unity clients.

SUMMARY STEPS

1. enable


3. no crypto xauth interface

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


Step 3 no crypto xauth interface

Example:

Router(config)# no crypto xauth ethernet0

Ignores XAUTH proposals for requests that are destined to the IP address of the interface. By default, Internet Key Exchange (IKE) processes XAUTH proposals.

Verifying VRF-Aware IPsec

To verify your VRF-Aware IPsec configurations, use the following show commands. These show commands allow you to list configuration information and security associations (SAs):

SUMMARY STEPS

1. enable

2. show crypto ipsec sa [map map-name| address | identity | interface interface | peer [vrf fvrf-name]

address | vrf ivrf-name] [detail]

3. show crypto isakmp key

4. show crypto isakmp profile

5. show crypto key pubkey-chain rsa

106


Clearing Security Associations

What to Do Next

DETAILED STEPS


Step 1 enable

Example:

Router> enable

Step 2 show crypto ipsec sa [map map-name| address |

identity | interface interface | peer [vrf fvrf-name]

address | vrf ivrf-name] [detail]

Example:

Router# show crypto ipsec sa vrf vpn1

Step 3 show crypto isakmp key

Example:

Router# show crypto isakmp key

Step 4 show crypto isakmp profile

Example:

Router# show crypto isakmp profile

Step 5 show crypto key pubkey-chain rsa

Example:

Router# show crypto key pubkey-chain rsa

Purpose



Allows you to view the settings used by current security associations (SAs).

Lists all the keyrings and their preshared keys.

• Use this command to verify your crypto keyring configuration.

Lists all ISAKMP profiles and their configurations.

Views the RSA public keys of the peer that are stored on your router.

• The output is extended to show the keyring to which the public key belongs.

Clearing Security Associations

The following clear commands allow you to clear SAs.

SUMMARY STEPS

1. enable

2. clear crypto sa [counters | map map-name | peer[vrf fvrf-name] address | spi address {ah | esp} spi |

vrf ivrf-name]


107

Troubleshooting VRF-Aware IPsec

What to Do Next

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable

Step 2 clear crypto sa [counters | map map-name | peer[vrf fvrf-name] address |

spi address {ah | esp} spi | vrf ivrf-name]

Clears the IPsec security associations

(SAs).

Example:

Router# clear crypto sa vrf VPN1

Troubleshooting VRF-Aware IPsec

To troubleshoot VRF-Aware IPsec, use the following debugcommands:

SUMMARY STEPS

1. enable

2. debug crypto ipsec


DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable

Step 2 debug crypto ipsec

Displays IP security (IPsec) events.

Example:

Router# debug crypto ipsec

Step 3 debug crypto isakmp

Displays messages about Internet Key Exchange (IKE) events.

Example:

Router(config)# debug crypto isakmp

108


VRF-Aware IPsec

Debug Examples for VRF-Aware IPsec

•

Debug Examples for VRF-Aware IPsec, page 109


The following sample debug outputs are for a VRF-aware IPsec configuration:

IPsec PE

Router# debug crypto ipsec

Crypto IPSEC debugging is on

IPSEC-PE#debug crypto isakmp

Crypto ISAKMP debugging is on

IPSEC-PE#debug crypto isakmp d

04:31:28: ISAKMP (0:12): purging SA., sa=6482B354, delme=6482B354

04:31:28: ISAKMP: Unlocking IKE struct 0x63C142F8 for declare_sa_dead(), count 0

IPSEC-PE#debug crypto isakmp detail

Crypto ISAKMP internals debugging is on

IPSEC-PE#

IPSEC-PE#

IPSEC-PE#

04:32:07: ISAKMP: Deleting peer node by peer_reap for 10.1.1.1: 63C142F8

04:32:55: ISAKMP cookie gen for src 172.16.1.1 dst 10.1.1.1

04:32:55: ISAKMP cookie 3123100B DC887D4E


04:32:55: ISAKMP cookie AA8F7B41 49A60E88


04:32:55: ISAKMP cookie 3123100B DBC8E125


04:32:55: ISAKMP cookie AA8F7B41 B4BDB5B7

04:32:55: ISAKMP (0:0): received packet from 10.1.1.1 dport 500 sport 500 Global (N) NEW

SA

04:32:55: ISAKMP: local port 500, remote port 500

04:32:55: ISAKMP: hash from 729FA94 for 619 bytes

04:32:55: ISAKMP: Packet hash:

64218CC0: B91E2C70 095A1346 9.,p.Z.F

64218CD0: 0EDB4CA6 8A46784F B314FD3B 00 .[L&.FxO.};.


04:32:55: ISAKMP cookie AA8F7B41 F7ACF384


04:32:55: ISAKMP cookie AA8F7B41 0C07C670

04:32:55: ISAKMP: insert sa successfully sa = 6482B354

04:32:55: ISAKMP (0:13): processing SA payload. message ID = 0

04:32:55: ISAKMP (0:13): processing ID payload. message ID = 0

04:32:55: ISAKMP (0:13): peer matches vpn2-ra profile

04:32:55: ISAKMP: Looking for a matching key for 10.1.1.1 in default

04:32:55: ISAKMP: Created a peer struct for 10.1.1.1, peer port 500

04:32:55: ISAKMP: Locking peer struct 0x640BBB18, IKE refcount 1 for crypto_ikmp_config_initialize_sa

04:32:55: ISAKMP (0:13): Setting client config settings 648252B0

04:32:55: ISAKMP (0:13): (Re)Setting client xauth list and state

04:32:55: ISAKMP (0:13): processing vendor id payload

04:32:55: ISAKMP (0:13): vendor ID seems Unity/DPD but major 157 mismatch

04:32:55: ISAKMP (0:13): vendor ID is NAT-T v3




04:32:55: ISAKMP (0:13) Authentication by xauth preshared

04:32:55: ISAKMP (0:13): Checking ISAKMP transform 1 against priority 1 policy

04:32:55: ISAKMP: encryption 3DES-CBC

04:32:55: ISAKMP: hash SHA

04:32:55: ISAKMP: default group 2

04:32:55: ISAKMP: auth XAUTHInitPreShared

04:32:55: ISAKMP: life type in seconds

04:32:55: ISAKMP: life duration (VPI) of 0x0 0x20 0xC4 0x9B

04:32:55: ISAKMP (0:13): atts are acceptable. Next payload is 3






109

VRF-Aware IPsec




04:32:55: ISAKMP (0:13): processing KE payload. message ID = 0

04:32:55: ISAKMP (0:13): processing NONCE payload. message ID = 0


04:32:55: ISAKMP (0:13): vendor ID is DPD



04:32:55: ISAKMP (0:13): vendor ID is XAUTH


04:32:55: ISAKMP (0:13): claimed IOS but failed authentication


04:32:55: ISAKMP (0:13): vendor ID is Unity

04:32:55: ISAKMP (0:13): Input = IKE_MESG_FROM_PEER, IKE_AM_EXCH

04:32:55: ISAKMP (0:13): Old State = IKE_READY New State = IKE_R_AM_AAA_AWAIT


04:32:55: ISAKMP cookie AA8F7B41 7AE6E1DF

04:32:55: ISAKMP: isadb_post_process_list: crawler: 4 AA 31 (6482B354)

04:32:55: crawler my_cookie AA8F7B41 F7ACF384

04:32:55: crawler his_cookie E46E088D F227FE4D

04:32:55: ISAKMP: got callback 1

04:32:55: ISAKMP (0:13): SKEYID state generated

04:32:55: ISAKMP: Unity/DPD ID: vendor_id_payload:

next: 0xD, reserved: 0x0, len 0x14

04:32:55: ISAKMP: Unity/DPD ID payload dump:

63E66D70: 0D000014 ....

63E66D80: 12F5F28C 457168A9 702D9FE2 74CC0100 .ur.Eqh)p-.btL..

63E66D90: 00 .

04:32:55: ISAKMP: Unity/DPD ID: vendor_id_payload:

next: 0xD, reserved: 0x0, len 0x14

04:32:55: ISAKMP: Unity/DPD ID payload dump:

63E66D90: 0D000014 AFCAD713 68A1F1C9 6B8696FC ..../JW.h!qIk..|

63E66DA0: 77570100 00 wW...

04:32:55: ISAKMP (0:13): constructed NAT-T vendor-03 ID

04:32:55: ISAKMP (0:13): SA is doing pre-shared key authentication plus XAUTH using id type ID_IPV4_ADDR

04:32:55: ISAKMP (13): ID payload

next-payload : 10

type : 1

addr : 172.16.1.1

protocol : 17

port : 0

length : 8

04:32:55: ISAKMP (13): Total payload length: 12

04:32:55: ISAKMP (0:13): constructed HIS NAT-D

04:32:55: ISAKMP (0:13): constructed MINE NAT-D

04:32:55: ISAKMP (0:13): sending packet to 10.1.1.1 my_port 500 peer_port 500 (R)

AG_INIT_EXCH

04:32:55: ISAKMP (0:13): Input = IKE_MESG_FROM_AAA, PRESHARED_KEY_REPLY

04:32:55: ISAKMP (0:13): Old State = IKE_R_AM_AAA_AWAIT New State = IKE_R_AM2


04:32:55: ISAKMP cookie 3123100B D99DA70D


04:32:55: ISAKMP cookie AA8F7B41 9C69F917

04:32:55: ISAKMP: isadb_post_process_list: crawler: 5 21FF 1 (6482B354)




04:32:55: ISAKMP cookie 3123100B 00583224


04:32:55: ISAKMP cookie AA8F7B41 C1B006EE




04:32:55: ISAKMP (0:13): received packet from 10.1.1.1 dport 500 sport 500 Global (R)

AG_INIT_EXCH

04:32:55: ISAKMP: hash from 7003A34 for 132 bytes


64218CC0: D1202D99 2BB49D38 Q -.+4.8

64218CD0: B8FBB1BE 7CDC67D7 4E26126C 63 8{1>|\gWN&.lc

04:32:55: ISAKMP (0:13): processing HASH payload. message ID = 0

04:32:55: ISAKMP:received payload type 17

04:32:55: ISAKMP (0:13): Detected NAT-D payload

110


VRF-Aware IPsec


04:32:55: ISAKMP (0:13): recalc my hash for NAT-D

04:32:55: ISAKMP (0:13): NAT match MINE hash

04:32:55: ISAKMP:received payload type 17

04:32:55: ISAKMP (0:13): Detected NAT-D payload

04:32:55: ISAKMP (0:13): recalc his hash for NAT-D

04:32:55: ISAKMP (0:13): NAT match HIS hash

04:32:55: ISAKMP (0:13): processing NOTIFY INITIAL_CONTACT protocol 1

spi 0, message ID = 0, sa = 6482B354

04:32:55: ISAKMP (0:13): Process initial contact, bring down existing phase 1 and 2 SA's with local 172.16.1.1 remote 10.1.1.1 remote port

500

04:32:55: ISAKMP (0:13): returning IP addr to the address pool


04:32:55: ISAKMP cookie AA8F7B41 05D315C5


04:32:55: ISAKMP cookie 3123100B 041A85A6

04:32:55: ISAKMP (0:13): SA has been authenticated with 10.1.1.1

04:32:55: ISAKMP: Trying to insert a peer 172.16.1.1/10.1.1.1/500/, and inserted successfully.

04:32:55: ISAKMP: set new node -803402627 to CONF_XAUTH

04:32:55: IPSEC(key_engine): got a queue event...


QM_IDLE

04:32:55: ISAKMP (0:13): purging node -803402627

04:32:55: ISAKMP: Sending phase 1 responder lifetime 86400

04:32:55: ISAKMP (0:13): Input = IKE_MESG_FROM_PEER, IKE_AM_EXCH

04:32:55: ISAKMP (0:13): Old State = IKE_R_AM2 New State = IKE_P1_COMPLETE


04:32:55: ISAKMP cookie AA8F7B41 25EEF256




04:32:55: ISAKMP (0:13): Need XAUTH

04:32:55: ISAKMP (0:13): Input = IKE_MESG_INTERNAL, IKE_PHASE1_COMPLETE

04:32:55: ISAKMP (0:13): Old State = IKE_P1_COMPLETE New State =

IKE_XAUTH_AAA_START_LOGIN_AWAIT


04:32:55: ISAKMP cookie AA8F7B41 2CCFA491

04:32:55: ISAKMP: isadb_post_process_list: crawler: B 27FF 12 (6482B354)




04:32:55: ISAKMP: set new node -1447732198 to CONF_XAUTH

04:32:55: ISAKMP/xauth: request attribute XAUTH_USER_NAME_V2

04:32:55: ISAKMP/xauth: request attribute XAUTH_USER_PASSWORD_V2

04:32:55: ISAKMP (0:13): initiating peer config to 10.1.1.1. ID = -1447732198


CONF_XAUTH

04:32:55: ISAKMP (0:13): Input = IKE_MESG_FROM_AAA, IKE_AAA_START_LOGIN

04:32:55: ISAKMP (0:13): Old State = IKE_XAUTH_AAA_START_LOGIN_AWAIT New State =

IKE_XAUTH_REQ_SENT

04:33:00: ISAKMP (0:13): retransmitting phase 2 CONF_XAUTH -1447732198 ...

04:33:00: ISAKMP (0:13): incrementing error counter on sa: retransmit phase 2

04:33:00: ISAKMP (0:13): incrementing error counter on sa: retransmit phase 2

04:33:00: ISAKMP (0:13): retransmitting phase 2 -1447732198 CONF_XAUTH


CONF_XAUTH


04:33:03: ISAKMP cookie 3123100B 124D4618


04:33:03: ISAKMP cookie AA8F7B41 B0C91917





04:33:03: ISAKMP cookie 3123100B 0E294692


04:33:03: ISAKMP cookie AA8F7B41 091A7695





CONF_XAUTH


111

VRF-Aware IPsec


04:33:03: ISAKMP: hash from 7292D74 for 92 bytes


64218CC0: 84A1AF24 5D92B116 .!/$].1.

64218CD0: FC2C6252 A472C5F8 152AC860 63 |,bR$rEx.*H`c

04:33:03: ISAKMP (0:13): processing transaction payload from 11.1.1.1. message ID =

-1447732198

04:33:03: ISAKMP: Config payload REPLY

04:33:03: ISAKMP/xauth: reply attribute XAUTH_USER_NAME_V2

04:33:03: ISAKMP/xauth: reply attribute XAUTH_USER_PASSWORD_V2

04:33:03: ISAKMP (0:13): deleting node -1447732198 error FALSE reason "done with xauth request/reply exchange"

04:33:03: ISAKMP (0:13): Input = IKE_MESG_FROM_PEER, IKE_CFG_REPLY

04:33:03: ISAKMP (0:13): Old State = IKE_XAUTH_REQ_SENT New State =

IKE_XAUTH_AAA_CONT_LOGIN_AWAIT


04:33:03: ISAKMP cookie AA8F7B41 A1B3E684





04:33:03: ISAKMP: set new node 524716665 to CONF_XAUTH

04:33:03: ISAKMP (0:13): initiating peer config to 10.1.1.1. ID = 524716665


CONF_XAUTH

04:33:03: ISAKMP (0:13): Input = IKE_MESG_FROM_AAA, IKE_AAA_CONT_LOGIN

04:33:03: ISAKMP (0:13): Old State = IKE_XAUTH_AAA_CONT_LOGIN_AWAIT New State =

IKE_XAUTH_SET_SENT


04:33:03: ISAKMP cookie 3123100B 5C83A09D


04:33:03: ISAKMP cookie AA8F7B41 2BEBEFD4





04:33:03: ISAKMP cookie 3123100B DA00A46B


04:33:03: ISAKMP cookie AA8F7B41 FDD27773





CONF_XAUTH



64218CC0: 5034B99E B8BA531F P49.8:S.

64218CD0: 6267B8BD F3006989 DC118796 63 bg8=s.i.\...c


524716665

04:33:03: ISAKMP: Config payload ACK

04:33:03: ISAKMP (0:13): XAUTH ACK Processed

04:33:03: ISAKMP (0:13): deleting node 524716665 error FALSE reason "done with transaction"

04:33:03: ISAKMP (0:13): Input = IKE_MESG_FROM_PEER, IKE_CFG_ACK

04:33:03: ISAKMP (0:13): Old State = IKE_XAUTH_SET_SENT New State = IKE_P1_COMPLETE


04:33:03: ISAKMP cookie AA8F7B41 E0BB50E9




04:33:03: ISAKMP (0:13): Input = IKE_MESG_INTERNAL, IKE_PHASE1_COMPLETE

04:33:03: ISAKMP (0:13): Old State = IKE_P1_COMPLETE New State = IKE_P1_COMPLETE


04:33:03: ISAKMP cookie 3123100B 7794EF6E


04:33:03: ISAKMP cookie AA8F7B41 C035AAE5





04:33:03: ISAKMP cookie 3123100B F1FCC25A


04:33:03: ISAKMP cookie AA8F7B41 31744F44

112


VRF-Aware IPsec






QM_IDLE

04:33:03: ISAKMP: set new node -1639992295 to QM_IDLE



64218CC0: 9D7DF4DF FE3A6403 .}t_~:d.

64218CD0: 3F1D1C59 C5D138CE 50289B79 07 ?..YEQ8NP(.y.


-1639992295

04:33:03: ISAKMP: Config payload REQUEST

04:33:03: ISAKMP (0:13): checking request:

04:33:03: ISAKMP: IP4_ADDRESS

04:33:03: ISAKMP: IP4_NETMASK

04:33:03: ISAKMP: IP4_DNS

04:33:03: ISAKMP: IP4_DNS

04:33:03: ISAKMP: IP4_NBNS

04:33:03: ISAKMP: IP4_NBNS

04:33:03: ISAKMP: SPLIT_INCLUDE

04:33:03: ISAKMP: DEFAULT_DOMAIN

04:33:03: ISAKMP (0:13): Input = IKE_MESG_FROM_PEER, IKE_CFG_REQUEST

04:33:03: ISAKMP (0:13): Old State = IKE_P1_COMPLETE New State =

IKE_CONFIG_AUTHOR_AAA_AWAIT


04:33:03: ISAKMP cookie AA8F7B41 B02E0D67

04:33:03: ISAKMP: isadb_post_process_list: crawler: C 27FF 12 (6482B354)




04:33:03: ISAKMP (0:13): attributes sent in message:

04:33:03: Address: 10.2.0.0

04:33:03: ISAKMP (0:13): allocating address 10.4.1.4

04:33:03: ISAKMP: Sending private address: 10.4.1.4

04:33:03: ISAKMP: Sending DEFAULT_DOMAIN default domain name: vpn2.com

04:33:03: ISAKMP (0:13): responding to peer config from 10.1.1.1. ID = -1639992295


CONF_ADDR

04:33:03: ISAKMP (0:13): deleting node -1639992295 error FALSE reason ""

04:33:03: ISAKMP (0:13): Input = IKE_MESG_FROM_AAA, IKE_AAA_GROUP_ATTR

04:33:03: ISAKMP (0:13): Old State = IKE_CONFIG_AUTHOR_AAA_AWAIT New State =

IKE_P1_COMPLETE


04:33:03: ISAKMP cookie 3123100B 881D5411


04:33:03: ISAKMP cookie AA8F7B41 6FD82541





04:33:03: ISAKMP cookie 3123100B 8A94C1BE


04:33:03: ISAKMP cookie AA8F7B41 F3BA766D





QM_IDLE

04:33:03: ISAKMP: set new node 17011691 to QM_IDLE

04:33:03: ISAKMP: hash from 70029F4 for 540 bytes


64218CC0: AFBA30B2 55F5BC2D /:02Uu<-

64218CD0: 3A86B1C9 00D2F5BA 77BF5589 07 :.1I.Ru:w?U..

04:33:03: ISAKMP (0:13): processing HASH payload. message ID = 17011691

04:33:03: ISAKMP (0:13): processing SA payload. message ID = 17011691

04:33:03: ISAKMP (0:13): Checking IPSec proposal 1

04:33:03: ISAKMP: transform 1, ESP_3DES

04:33:03: ISAKMP: attributes in transform:

04:33:03: ISAKMP: encaps is 1

04:33:03: ISAKMP: SA life type in seconds

04:33:03: ISAKMP: SA life duration (VPI) of 0x0 0x20 0xC4 0x9B

04:33:03: ISAKMP: SA life type in kilobytes


113

VRF-Aware IPsec


04:33:03: ISAKMP: SA life duration (VPI) of 0x0 0x46 0x50 0x0

04:33:03: ISAKMP: authenticator is HMAC-SHA

04:33:03: ISAKMP (0:13): atts are acceptable.

04:33:03: IPSEC(validate_proposal_request): proposal part #1,

(key eng. msg.) INBOUND local= 172.18.1.1, remote= 10.1.1.1,

local_proxy= 0.0.0.0/0.0.0.0/0/0 (type=4),

remote_proxy= 10.4.1.4/255.255.255.255/0/0 (type=1),

protocol= ESP, transform= esp-3des esp-sha-hmac,

lifedur= 0s and 0kb,

spi= 0x0(0), conn_id= 0, keysize= 0, flags= 0x2

04:33:03: IPSEC(kei_proxy): head = ra, map->ivrf = vpn1, kei->ivrf = vpn2


04:33:03: IPSEC(validate_transform_proposal): transform proposal not supported for identity:

{esp-3des esp-sha-hmac}

04:33:03: ISAKMP (0:13): IPSec policy invalidated proposal

04:33:03: ISAKMP (0:13): Checking IPSec proposal 2

04:33:03: ISAKMP: transform 1, ESP_3DES

04:33:03: ISAKMP: attributes in transform:

04:33:03: ISAKMP: encaps is 1

04:33:03: ISAKMP: SA life type in seconds

04:33:03: ISAKMP: SA life duration (VPI) of 0x0 0x20 0xC4 0x9B

04:33:03: ISAKMP: SA life type in kilobytes

04:33:03: ISAKMP: SA life duration (VPI) of 0x0 0x46 0x50 0x0

04:33:03: ISAKMP: authenticator is HMAC-MD5

04:33:03: ISAKMP (0:13): atts are acceptable.

04:33:03: IPSEC(validate_proposal_request): proposal part #1,


local_proxy= 0.0.0.0/0.0.0.0/0/0 (type=4),


protocol= ESP, transform= esp-3des esp-md5-hmac,


spi= 0x0(0), conn_id= 0, keysize= 0, flags= 0x2



04:33:03: ISAKMP (0:13): processing NONCE payload. message ID = 17011691



04:33:03: ISAKMP (0:13): asking for 1 spis from ipsec

04:33:03: ISAKMP (0:13): Node 17011691, Input = IKE_MESG_FROM_PEER, IKE_QM_EXCH

04:33:03: ISAKMP (0:13): Old State = IKE_QM_READY New State = IKE_QM_SPI_STARVE


04:33:03: IPSEC(spi_response): getting spi 2749516541 for SA

from 172.18.1.1 to 10.1.1.1 for prot 3

04:33:03: ISAKMP: received ke message (2/1)


next-payload : 5

type : 1

addr : 10.4.1.4

protocol : 0

port : 0


next-payload : 11

type : 4

addr : 0.0.0.0

protocol : 0

port : 0


QM_IDLE

04:33:04: ISAKMP (0:13): Node 17011691, Input = IKE_MESG_FROM_IPSEC, IKE_SPI_REPLY

04:33:04: ISAKMP (0:13): Old State = IKE_QM_SPI_STARVE New State = IKE_QM_R_QM2


04:33:04: ISAKMP cookie 3123100B 93DE46D2


04:33:04: ISAKMP cookie AA8F7B41 088A0A16





04:33:04: ISAKMP cookie 3123100B A8F23F73


04:33:04: ISAKMP cookie AA8F7B41 93D8D879


114


VRF-Aware IPsec

Configuration Examples for VRF-Aware IPsec




QM_IDLE

04:33:04: ISAKMP: hash from 7290DB4 for 60 bytes


64218CC0: 4BB45A92 7181A2F8 K4Z.q."x

64218CD0: 73CC12F8 091875C0 054F77CD 63 [email protected]

04:33:04: ISAKMP: Locking peer struct 0x640BBB18, IPSEC refcount 1 for stuff_ke

04:33:04: ISAKMP (0:13): Creating IPSec SAs

04:33:04: inbound SA from 10.1.1.1 to 172.18.1.1 (f/i) 0/ 2

(proxy 10.4.1.4 to 0.0.0.0)

04:33:04: has spi 0xA3E24AFD and conn_id 5127 and flags 2

04:33:04: lifetime of 2147483 seconds

04:33:04: lifetime of 4608000 kilobytes

04:33:04: has client flags 0x0

04:33:04: outbound SA from 172.18.1.1 to 10.1.1.1 (f/i) 0/ 2 (proxy

0.0.0.0 to 10.4.1.4 )

04:33:04: has spi 1343294712 and conn_id 5128 and flags A

04:33:04: lifetime of 2147483 seconds

04:33:04: lifetime of 4608000 kilobytes

04:33:04: has client flags 0x0

04:33:04: ISAKMP (0:13): deleting node 17011691 error FALSE reason "quick mode done

(await)"

04:33:04: ISAKMP (0:13): Node 17011691, Input = IKE_MESG_FROM_PEER, IKE_QM_EXCH

04:33:04: ISAKMP (0:13): Old State = IKE_QM_R_QM2 New State = IKE_QM_PHASE2_COMPLETE


04:33:04: IPSEC(initialize_sas): ,


local_proxy= 0.0.0.0/0.0.0.0/0/0 (type=4),


protocol= ESP, transform= esp-3des esp-md5-hmac ,


spi= 0xA3E24AFD(2749516541), conn_id= 5127, keysize= 0, flags= 0x2

04:33:04: IPSEC(initialize_sas): ,

(key eng. msg.) OUTBOUND local= 172.18.1.1, remote= 10.1.1.1,

local_proxy= 0.0.0.0/0.0.0.0/0/0 (type=4),


protocol= ESP, transform= esp-3des esp-md5-hmac,


spi= 0x50110CF8(1343294712), conn_id= 5128, keysize= 0, flags= 0xA



04:33:04: IPSEC(rte_mgr): VPN Route Added 10.4.1.4 255.255.255.255 via 10.1.1.1 in vpn2

04:33:04: IPSEC(add mtree): src 0.0.0.0, dest 10.4.1.4, dest_port 0

04:33:04: IPSEC(create_sa): sa created,

(sa) sa_dest= 172.18.1.1, sa_prot= 50,

sa_spi= 0xA3E24AFD(2749516541),

sa_trans= esp-3des esp-md5-hmac, sa_conn_id= 5127

04:33:04: IPSEC(create_sa): sa created,

(sa) sa_dest= 10.1.1.1, sa_prot= 50,

sa_spi= 0x50110CF8(1343294712),

sa_trans= esp-3des esp-md5-hmac, sa_conn_id= 5128

04:33:53: ISAKMP (0:13): purging node -1639992295

04:33:54: ISAKMP (0:13): purging node 17011691


•

Example Static IPsec-to-MPLS VPN, page 116

•

Example IPsec-to-MPLS VPN Using RSA Encryption, page 117

•

Example IPsec-to-MPLS VPN with RSA Signatures, page 119

•

Example IPsec Remote Access-to-MPLS VPN, page 120

•

Upgrade from Previous Versions of the Cisco Network-Based IPsec VPN Solution, page 121


115

Example Static IPsec-to-MPLS VPN


Example Static IPsec-to-MPLS VPN

The following sample shows a static configuration that maps IPsec tunnels to MPLS VPNs. The configurations map IPsec tunnels to MPLS VPNs “VPN1” and “VPN2.” Both of the IPsec tunnels terminate on a single public-facing interface.

IPsec PE Configuration

ip vrf vpn1

rd 100:1

route-target export 100:1

route-target import 100:1

!

ip vrf vpn2

rd 101:1



!

crypto keyring vpn1

pre-shared-key address 172.16.1.1 key vpn1 crypto keyring vpn2

pre-shared-key address 10.1.1.1 key vpn2

!


encr 3des


group 2

!

crypto isakmp profile vpn1

vrf vpn1

keyring vpn1


! crypto isakmp profile vpn2

vrf vpn2

keyring vpn2


!

crypto ipsec transform-set vpn1 esp-3des esp-sha-hmac crypto ipsec transform-set vpn2 esp-3des esp-md5-hmac

!

crypto map crypmap 1 ipsec-isakmp

set peer 172.16.1.1

set transform-set vpn1

set isakmp-profile vpn1

match address 101 crypto map crypmap 3 ipsec-isakmp

set peer 10.1.1.1



match address 102

!

interface Ethernet1/1

ip address 172.17.1.1 255.255.0.0

tag-switching ip

!


ip address 172.18.1.1 255.255.255.0

crypto map crypmap

!

ip route 172.16.1.1 255.255.255.255 172.18.1.2

ip route 10.1.1.1 255.255.255.255 172.18.1.2

ip route vrf vpn1 10.2.0.0 255.255.0.0 172.18.1.2 global ip route vrf vpn2 10.2.0.0 255.255.0.0 172.18.1.2 global

!

access-list 101 permit ip 10.1.0.0 0.0.255.255 10.2.0.0 0.0.255.255


116


Example IPsec-to-MPLS VPN Using RSA Encryption


IPsec Customer Provided Edge (CPE) Configuration for VPN1


encr 3des


group 2 crypto isakmp key vpn1 address 172.18.1.1

!

!

crypto ipsec transform-set vpn1 esp-3des esp-sha-hmac

!

crypto map vpn1 1 ipsec-isakmp

set peer 172.18.1.1


match address 101

!


ip address 172.16.1.1 255.255.255.0

crypto map vpn1

!


ip address 10.2.1.1 255.255.0.0

!


!

IPsec CPE Configuration for VPN2


encr 3des


group 2

!

crypto isakmp key vpn2 address 172.18.1.1

!

!

crypto ipsec transform-set vpn2 esp-3des esp-md5-hmac

!


set peer 172.18.1.1


match address 101

!

interface FastEthernet0

ip address 10.1.1.1 255.255.255.0

crypto map vpn2

!


ip address 10.2.1.1 255.255.0.0

!


Example IPsec-to-MPLS VPN Using RSA Encryption

The following example shows an IPsec-to-MPLS configuration using RSA encryption:

PE Router Configuration

ip vrf vpn1

rd 100:1



!


authentication rsa-encr

!

crypto keyring vpn1


117

VRF-Aware IPsec


rsa-pubkey address 172.16.1.1 encryption

key-string

305C300D 06092A86 4886F70D 01010105 00034B00 30480241 00DBF381 00DDECC8

DC4AA490 40320C52 9912D876 EB36717C 63DCA95C 7E5EC02A 84F276CE 292B42D7

D664F324 3726F4E0 39D33093 ECB81B95 482511A5 F064C4B3 D5020301 0001

quit

! crypto isakmp profile vpn1

vrf vpn1

keyring vpn1


! crypto ipsec transform-set vpn1 esp-3des esp-sha-hmac

!


set peer 172.16.1.1



match address 101

!


ip address 172.17.1.1 255.255.0.0

tag-switching ip

!


ip address 172.18.1.1 255.255.255.0

crypto map crypmap

!

ip route 172.16.1.1 255.255.255.255 172.18.1.2

ip route vrf vpn1 10.2.0.0 255.255.0.0 172.18.1.2 global

!




authentication rsa-encr

!

crypto key pubkey-chain rsa

addressed-key 172.18.1.1 encryption

key-string

3082011B 300D0609 2A864886 F70D0101 01050003 82010800 30820103 0281FB00

C90CC78A 6002BDBA 24683396 B7D7877C 16D08C47 E00C3C10 63CF13BC 4E09EA23

92EB8A48 4113F5A4 8796C8BE AD7E2DC1 3B0742B6 7118CE7C 1B0E21D1 AA9724A4

4D74FCEA 562FF225 A2B11F18 E53C4415 61C3B741 3A06E75D B4F9102D 6163EE40

16C68FD7 6532F660 97B59118 9C8DE3E5 4E2F2925 BBB87FCB 95223D4E A5E362DB

215CB35C 260080805 17BBE1EF C3050E13 031F3D5B 5C22D16C FC8B1EC5 074F07A5

D050EC80 7890D9C5 EC20D6F0 173FE2BA 89F5B5F9 2EADC9A6 D461921E 3D5B60016

ABB8B6B9 E2124A21 93F0E4AE B487461B E7F1F1C4 032A0B0E 80DC3E15 CB268EC9

5D76B9BD 3C78CB75 CE9F68C6 484D6573 CBC3EB59 4B5F3999 8F9D0203 010001

quit

!


!


set peer 172.18.1.1


match address 101

!


ip address 172.16.1.1 255.255.255.0

crypto map vpn1

!


ip address 10.2.1.1 255.255.0.0

!


!

118


Example IPsec-to-MPLS VPN with RSA Signatures


Example IPsec-to-MPLS VPN with RSA Signatures

The following shows an IPsec-to-MPLS VPN configuration using RSA signatures:


ip vrf vpn1

rd 100:1



!

crypto ca trustpoint bombo

enrollment url http://172.31.68.59:80

crl optional

!

crypto ca certificate chain bombo

certificate 03C0

308203BF 308202A7 A0030201 02020203 C0300D06 092A8648 86F70D01 01050500

. . .

quit

certificate ca 01

30820379 30820261 A0030201 02020101 300D0609 2A864886 F70D0101 05050030

. . .

quit

!

crypto isakmp profile vpn1

vrf vpn1

ca trust-point bombo


! crypto ipsec transform-set vpn1 esp-3des esp-sha-hmac

!


set peer 172.16.1.1



match address 101

!


ip address 172.31.1.1 255.255.0.0

tag-switching ip

!


ip address 172.18.1.1 255.255.255.0

crypto map crypmap

!

ip route 172.16.1.1 255.255.255.255 172.18.1.2

ip route vrf vpn1 10.2.0.0 255.255.0.0 172.18.1.2 global

!


!


crypto ca trustpoint bombo

enrollment url http://172.31.68.59:80

crl optional

!

crypto ca certificate chain bombo

certificate 03BF

308203BD 308202A5 A0030201 02020203 BF300D06 092A8648 86F70D01 01050500

. . .

quit

certificate ca 01

30820379 30820261 A0030201 02020101 300D0609 2A864886 F70D0101 05050030

. . .

quit

!


119

Example IPsec Remote Access-to-MPLS VPN



!


set peer 172.18.1.1


match address 101

!


ip address 172.16.1.1 255.255.255.0

crypto map vpn1

!


ip address 10.2.1.1 255.255.0.0

!


!

Example IPsec Remote Access-to-MPLS VPN

The following shows an IPsec remote access-to-MPLS VPN configuration. The configuration maps IPsec tunnels to MPLS VPNs. The IPsec tunnels terminate on a single public-facing interface.


aaa new-model

!

aaa group server radius vpn1

server-private 10.1.1.1 auth-port 1645 acct-port 1646 timeout 5 retransmit 3 key vpn1

!

aaa group server radius vpn2

server-private 10.1.1.1 auth-port 1645 acct-port 1646 timeout 5 retransmit 3 key vpn2

!

aaa authorization network aaa-list group radius

!

ip vrf vpn1

rd 100:1



!

ip vrf vpn2

rd 101:1



!

crypto isakmp profile vpn1-ra

vrf vpn1

match identity group vpn1-ra

client authentication list vpn1

isakmp authorization list aaa-list

client configuration address initiate

client configuration address respond crypto isakmp profile vpn2-ra

vrf vpn2

match identity group vpn2-ra

client authentication list vpn2

isakmp authorization list aaa-list



!

!

crypto ipsec transform-set vpn1 esp-3des esp-sha-hmac crypto ipsec transform-set vpn2 esp-3des esp-md5-hmac

!

crypto dynamic-map vpn1 1


set isakmp-profile vpn1-ra

reverse-route

!

crypto dynamic-map vpn2 1

120


Upgrade from Previous Versions of the Cisco Network-Based IPsec VPN Solution

Site-to-Site Configuration Upgrade


set isakmp-profile vpn2-ra

reverse-route

!

!

crypto map ra 1 ipsec-isakmp dynamic vpn1 crypto map ra 2 ipsec-isakmp dynamic vpn2

!


ip address 172.17.1.1 255.255.0.0

tag-switching ip

!


ip address 172.18.1.1 255.255.255.0

crypto map ra

!

ip local pool vpn1-ra 10.4.1.1 10.4.1.254 group vpn1-ra ip local pool vpn2-ra 10.4.1.1 10.4.1.254 group vpn2-ra

!

Upgrade from Previous Versions of the Cisco Network-Based IPsec VPN

Solution

The VRF-Aware IPsec feature in the Cisco network-based IPsec VPN solution release 1.5 requires that you change your existing configurations. The following sample configurations indicate the changes you must make to your existing configurations.

•

Site-to-Site Configuration Upgrade, page 121

•

Remote Access Configuration Upgrade, page 122

•

Combination Site-to-Site and Remote Access Configuration Upgrade, page 124

Site-to-Site Configuration Upgrade

The following configurations show the changes that are necessary for a site-to-site configuration upgrade from a previous version of the network-based IPsec VPN solution to the Cisco network-based IPsec VPN solution release 1.5:

•

Previous Version Site-to-Site Configuration, page 121

•

New Version Site-to-Site Configuration, page 122

Previous Version Site-to-Site Configuration

crypto isakmp key VPN1 address 172.21.25.74

crypto isakmp key VPN2 address 172.21.21.74

!

crypto ipsec transform-set VPN1 esp-des esp-sha-hmac

crypto ipsec transform-set VPN2 esp-3des esp-sha-hmac

!

crypto map VPN1 10 ipsec-isakmp

set peer 172.21.25.74

set transform-set VPN1

match address 101

!


set peer 172.21.21.74


match address 102

!

interface FastEthernet0/0.1

encapsulation dot1Q 1 native

ip vrf forwarding VPN1

ip address 172.21.25.73 255.255.255.0


121

VRF-Aware IPsec

New Version Site-to-Site Configuration

crypto map VPN1

!




ip address 172.21.21.74 255.255.255.0

crypto map VPN2

New Version Site-to-Site Configuration

The following is an upgraded version of the same site-to-site configuration to the Cisco network-based

IPsec VPN solution release 1.5 solution:

Note

You must change two keyrings. The VRF-Aware Upset feature requires that keys be associated with a VRF if the IKE local endpoint is in the VRF.

crypto keyring VPN1-KEYS vrf VPN1

pre-shared-key address 172.21.25.74 key VPN1

!



!



!


set peer 172.21.25.74


match address 101

!


set peer 172.21.21.74


match address 102

!




ip address 172.21.25.73 255.255.255.0

crypto map VPN1

!




ip address 172.21.21.74 255.255.255.0

crypto map VPN2

Remote Access Configuration Upgrade

The following configurations show the changes that are necessary for a remote access configuration upgrade from a previous version of the network-based IPsec VPN solution to the Cisco network-based

IPsec VPN solution release 1.5:

•

Previous Version Remote Access Configuration, page 122

•

New Version Remote Access Configuration, page 123

Previous Version Remote Access Configuration

crypto isakmp client configuration group VPN1-RA-GROUP

key VPN1-RA

pool VPN1-RA

122


VRF-Aware IPsec

New Version Remote Access Configuration

!


key VPN2-RA

pool VPN2-RA

!

crypto ipsec transform-set VPN1-RA esp-3des esp-sha-hmac

crypto ipsec transform-set VPN2-RA esp-3des esp-md5-hmac

!

crypto dynamic-map VPN1-RA 1

set transform-set VPN1-RA

reverse-route

!



reverse-route

!

!

crypto map VPN1 client authentication list VPN1-RA-LIST

crypto map VPN1 isakmp authorization list VPN1-RA-LIST

crypto map VPN1 client configuration address initiate

crypto map VPN1 client configuration address respond

crypto map VPN1 10 ipsec-isakmp dynamic VPN1-RA

!






!




ip address 172.21.25.73 255.255.255.0

crypto map VPN1

!




ip address 172.21.21.74 255.255.255.0

crypto map VPN2

New Version Remote Access Configuration

In the following instance, there is no upgrade; it is recommended that you change to the following configuration: crypto isakmp client configuration group VPN1-RA-GROUP

key VPN1-RA

pool VPN1-RA

!


key VPN2-RA

pool VPN2-RA

!

crypto isakmp profile VPN1-RA

match identity group VPN1-RA-GROUP

client authentication list VPN1-RA-LIST

isakmp authorization list VPN1-RA-LIST



!







!



!


123

VRF-Aware IPsec

Combination Site-to-Site and Remote Access Configuration Upgrade



set isakmp-profile VPN1-RA

reverse-route

!




reverse-route

!


!


!




ip address 172.21.25.73 255.255.255.0

crypto map VPN1

!




ip address 172.21.21.74 255.255.255.0

crypto map VPN2

Combination Site-to-Site and Remote Access Configuration Upgrade

The following configurations show the changes that are necessary for a site-to-site and remote access configuration upgrade from a previous version of the network-based IPsec VPN solution to the Cisco network-based IPsec VPN solution release 1.5:

•

Previous Version Site-to-Site and Remote Access Configuration, page 124

•

New Version Site-to-Site and Remote Access Configuration, page 125

Previous Version Site-to-Site and Remote Access Configuration

crypto isakmp key VPN1 address 172.21.25.74 no-xauth crypto isakmp key VPN2 address 172.21.21.74 no-xauth

!


key VPN1-RA

pool VPN1-RA

!


key VPN2-RA

pool VPN2-RA

!



!



!



reverse-route

!



reverse-route

!






set peer 172.21.25.74

124


VRF-Aware IPsec

New Version Site-to-Site and Remote Access Configuration


match address 101


!






set peer 172.21.21.74


match address 102


!




ip address 172.21.25.73 255.255.255.0

crypto map VPN1

!




ip address 172.21.21.74 255.255.255.0

crypto map VPN2

New Version Site-to-Site and Remote Access Configuration

You must upgrade to this configuration:

Note

For site-to-site configurations that do not require XAUTH, configure an ISAKMP profile without XAUTH configuration. For remote access configurations that require XAUTH, configure an ISAKMP profile with

XAUTH.



!



!


key VPN1-RA

pool VPN1-RA

!


key VPN2-RA

pool VPN2-RA

!

crypto isakmp profile VPN1

keyring VPN1-KEYS

match identity address 172.21.25.74 VPN1

!

crypto isakmp profile VPN2

keyring VPN2-KEYS

match identity address 172.21.21.74 VPN2

!







!







125

VRF-Aware IPsec



!



!



!




reverse-route

!




reverse-route

!


set peer 172.21.25.74


set isakmp-profile VPN1

match address 101


!


set peer 172.21.21.74


set isakmp-profile VPN2

match address 102


!




ip address 172.21.25.73 255.255.255.0

crypto map VPN1

!




ip address 172.21.21.74 255.255.255.0

crypto map VPN2



Related Topic

IPsec configuration tasks

IPsec commands

IKE Phase 1 and Phase 2, aggressive mode, and main mode

IKE dead peer detection

Document Title

“ Configuring Security for VPNs with IPsec”


“Configuring Internet Key Exchange for IPsec

VPNs”

“Easy VPN Server”

126


VRF-Aware IPsec

Feature Information for VRF-Aware IPsec

Standards

Standard

None

MIBs

MIB

None

Title

--

MIBs Link

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following


RFCs

RFC

None

Title

--


Description



Link


Feature Information for VRF-Aware IPsec






127

VRF-Aware IPsec

Glossary

Table 7 Feature Information for VRF-Aware IPsec

Feature Name

VRF-Aware IPsec

Releases

12.2(15)T

15.1(1)S


The VRF-Aware IPsec feature introduces IP Security (IPsec) tunnel mapping to Multiprotocol

Label Switching (MPLS) Virtual

Private Networks (VPNs). Using the VRF-Aware IPsec feature, you can map IPsec tunnels to

Virtual Routing and Forwarding

(VRF) instances using a single public-facing address.

This feature was introduced in

Cisco IOS Release 12.2(15)T.


The following commands were introduced or modified: address,

ca trust-point, client

authentication list, client

configuration address, crypto

isakmp profile, crypto keyring,

crypto map isakmp-profile,

initiate-mode, isakmp

authorization list, keepalive

(isakmp profile), keyring, key-

string, match identity, no

crypto xauth, pre-shared-key,

quit, rsa-pubkey, self-identity,

serial-number, set isakmp-

profile, show crypto isakmp

key, show crypto isakmp

profile, vrf, clear crypto sa,

crypto isakmp peer, crypto map

isakmp-profile, show crypto

dynamic-map, show crypto

ipsec sa, show crypto isakmp sa,

show crypto map (IPsec).


Cisco IOS Release 15.1(1)S.

Glossary

CA --certification authority. CA is an entity that issues digital certificates (especially X.509 certificates) and vouches for the binding between the data items in a certificate.

128


VRF-Aware IPsec

CLI --command-line-interface. CLI is an interface that allows the user to interact with the operating system by entering commands and optional arguments. The UNIX operating system and DOS provide CLIs.

client --Corresponding IPsec IOS peer of the UUT in the Multi Protocol Label Switching (MPLS) network.

dead peer --IKE peer that is no longer reachable.

DN --Distinguished Name. A DN is the global, authoritative name of an entry in the Open System

Interconnection (OSI Directory [X.500]).

FQDN --fully qualified domain name. A FQDN is the full name of a system rather than just its host name.

For example, aldebaran is a host name, and aldebaran.interop.com is an FQDN.

FR --Frame Relay. FR is an industry-standard, switch-data-link-layer protocol that handles multiple virtual circuits using high-level data link (HDLC) encapsulation between connected devices. Frame Relay is more efficient than X.25, the protocol for which it generally is considered a replacement.

FVRF --Front Door Virtual Routing and Forwarding (VRF) repository. FVRF is the VRF used to route the encrypted packets to the peer.

IDB --Interface descriptor block. An IDB subblock is an area of memory that is private to an application.

This area stores private information and states variables that an application wants to associate with an IDB or an interface. The application uses the IDB to register a pointer to its subblock, not to the contents of the subblock itself.

IKE --Internet Key Exchange. IKE establishes a shared security policy and authenticates keys for services

(such as IPsec) that require keys. Before any IPsec traffic can be passed, each router, firewall, and host must verify the identity of its peer. This can be done by manually entering preshared keys into both hosts or by a CA service.

IKE keepalive --Bidirectional mechanism for determining the liveliness of an IKE peer.

IPsec --Security protocol for IP.

IVRF --Inside Virtual Routing and Forwarding. IVRF is the VRF of the plaintext packets.

MPLS --Multiprotocol Label Switching. MPLS is a switching method that forwards IP traffic using a label.

This label instructs the routers and the switches in the network where to forward the packets based on preestablished IP routing information.

RSA --Rivest, Shamir, and Adelman are the inventors of the RSA technique. The RSA technique is a public-key cryptographic system that can be used for encryption and authentication.

SA --Security Association. SA is an instance of security policy and keying material applied to a data flow.

VPN --Virtual Private Network. A VPN enables IP traffic to travel securely over a public TCP or IP network by encrypting all traffic from one network to another. A VPN uses “tunneling” to encrypt all information at the IP level.

VRF --Virtual Route Forwarding. VRF is A VPN routing and forwarding instance. A VRF consists of an

IP routing table, a derived forwarding table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table. In general, a VRF includes the routing information that defines a customer VPN site that is attached to a PE router.

XAUTH --Extended authentication. XAUTH is an optional exchange between IKE Phase 1 and IKE Phase

2, in which the router demands additional authentication information in an attempt to authenticate the actual user (as opposed to authenticating the peer).


129

VRF-Aware IPsec





130



The IKE: Initiate Aggressive Mode feature allows you to specify RADIUS tunnel attributes for an IP security (IPsec) peer and to initiate an Internet Key Exchange (IKE) aggressive mode negotiation with the tunnel attributes. This feature is best implemented in a crypto hub-and-spoke scenario, by which the spokes initiate IKE aggressive mode negotiation with the hub by using the preshared keys that are specified as tunnel attributes and stored on the AAA server. This scenario is scalable because the preshared keys are kept at a central repository (the AAA server) and more than one hub router and one application can use the information.

•


•

Prerequisites for IKE Initiate Aggressive Mode, page 131

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Restrictions for IKE Initiate Aggressive Mode, page 132

•

Information About IKE Initiate Aggressive Mode, page 132

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How to Configure IKE Initiate Aggressive Mode, page 132

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Configuration Examples for IKE Initiate Aggressive Mode, page 135

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•

Feature Information for IKE Initiate Aggressive Mode, page 137





Prerequisites for IKE Initiate Aggressive Mode

Before configuring the Initiate Aggressive Mode IKE feature, you must perform the following tasks:

• Configure AAA

• Configure an IPsec Transform

• Configure a static crypto map

• Configure an Internet Security Association and Key Management Protocol (ISAKMP) policy

• Configure a dynamic crypto map


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Overview

Restrictions for IKE Initiate Aggressive Mode

Restrictions for IKE Initiate Aggressive Mode

TED Restriction

This feature is not intended to be used with a dynamic crypto map that uses Tunnel Endpoint Discovery

(TED) to initiate tunnel setup. TED is useful in configuring a full mesh setup, which requires an AAA server at each site to store the preshared keys for the peers; this configuration is not practical for use with this feature.

Tunnel-Client-Endpoint ID Types

Only the following ID types can be used in this feature:

• ID_IPV4 (IPV4 address)

• ID_FQDN (fully qualified domain name, for example “foo.cisco.com”)

• ID_USER_FQDN (e-mail address)

Information About IKE Initiate Aggressive Mode

•

Overview, page 132

•

RADIUS Tunnel Attributes, page 132

Overview

The IKE: Initiate Aggressive Mode feature allows you to configure IKE preshared keys as RADIUS tunnel attributes for IPsec peers. Thus, you can scale your IKE preshared keys in a hub-and-spoke topology.

Although IKE preshared keys are simple to understand and easy to deploy, they do not scale well with an increasing number of users and are therefore prone to security threats. Instead of keeping your preshared keys on the hub router, this feature allows you to scale your preshared keys by storing and retrieving them from an authentication, authorization, and accounting (AAA) server. The preshared keys are stored in the

AAA server as Internet Engineering Task Force (IETF) RADIUS tunnel attributes and are retrieved when a user tries to “speak” to the hub router. The hub router retrieves the preshared key from the AAA server and the spokes (the users) initiate aggressive mode to the hub by using the preshared key that is specified in the

Internet Security Association Key Management Policy (ISAKMP) peer policy as a RADIUS tunnel attribute.

RADIUS Tunnel Attributes

To initiate an IKE aggressive mode negotiation, the Tunnel-Client-Endpoint (66) and Tunnel-Password

(69) attributes must be configured in the ISAKMP peer policy. The Tunnel-Client-Endpoint attribute will be communicated to the server by encoding it in the appropriate IKE identity payload; the Tunnel-Password attribute will be used as the IKE preshared key for the aggressive mode negotiation

How to Configure IKE Initiate Aggressive Mode

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Configuring RADIUS Tunnel Attributes, page 133

132


Configuring RADIUS Tunnel Attributes


•

Verifying RADIUS Tunnel Attribute Configurations, page 134

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Configuring RADIUS Tunnel Attributes

To configure the Tunnel-Client-Endpoint and Tunnel-Password attributes within the ISAKMP peer configuration, perform the following steps.

SUMMARY STEPS

1. enable


3. crypto map map-name isakmp authorization list list-name

4. crypto isakmp peer {ip-address ip-address | fqdn fqdn}

5. set aggressive-mode client-endpoint client-endpoint

6. set aggressive-mode password password

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable



Example:


Step 3 crypto map map-name isakmp authorization list list-name

Example:

Router (config)# crypto map testmap10 isakmp authorization list list ike

Step 4 crypto isakmp peer {ip-address ip-address | fqdn fqdn}

Example:

Router (config)# crypto isakmp peer ip address

10.10.10.1

Enables IKE querying of AAA for tunnel attributes in aggressive mode.

Enables an IPsec peer for IKE querying of AAA for tunnel attributes in aggressive mode and enters

ISAKMP policy configuration mode.


133

Verifying RADIUS Tunnel Attribute Configurations



Step 5 set aggressive-mode client-endpoint client-endpoint

Example:

Router (config-isakmp)# set aggressive-mode clientendpoint user-fqdn [email protected]

Step 6 set aggressive-mode password password

Example:

Router (config-isakmp)#set aggressive-mode password cisco123

Purpose

Specifies the Tunnel-Client-Endpoint attribute within an ISAKMP peer configuration.

Specifies the Tunnel-Password attribute within an

ISAKMP peer configuration.

Verifying RADIUS Tunnel Attribute Configurations

To verify that the Tunnel-Client-Endpoint and Tunnel-Password attributes have been configured within the

ISAKMP peer policy, use the show running-configglobal configuration command.


To troubleshoot the IKE: Initiate Aggressive Mode feature, perform the following steps.

SUMMARY STEPS

1. enable

2. debug aaa authorization


4. debug radius

DETAILED STEPS


Step 1 enable

Purpose



Example:

Router> enable

Step 2

debug aaa authorization Displays information about AAA authorization.

Example:

Router# debug aaa authorization

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Hub Configuration Example

Configuration Examples for IKE Initiate Aggressive Mode


Step 3

debug crypto isakmp

Example:

Router# debug crypto isakmp

Step 4

debug radius

Example:

Router# debug radius

Purpose

Displays messages about IKE events.

Displays information associated with RADIUS.

Configuration Examples for IKE Initiate Aggressive Mode

•

Hub Configuration Example, page 135

•

Spoke Configuration Example, page 136

•

RADIUS User Profile Example, page 136

Hub Configuration Example

The following example shows how to configure a hub for a hub-and-spoke topology that supports aggressive mode using RADIUS tunnel attributes:

!The AAA configurations are as follows: aaa new-model aaa authorization network ike group radius aaa authentication login default group radius

!

! The Radius configurations are as follows: radius-server host 10.1.1.1 auth-port 1645 acct-port 1646 radius-server key rad123

!

! The IKE configurations are as follows: crypto isakmp policy 1


!

! The IPsec configurations are as follows: crypto ipsec transform-set trans1 esp-3des esp-sha-hmac

!

crypto dynamic-map Dmap 10

set transform-set trans1

!

crypto map Testtag isakmp authorization list ike crypto map Testtag 10 ipsec-isakmp dynamic Dmap

!


ip address 10.4.4.1 255.255.255.0

crypto map Testtag

!


ip address 10.2.2.1 255.255.255.0


135

Spoke Configuration Example


Spoke Configuration Example

The following example shows how to configure a spoke for a hub-and-spoke topology that supports aggressive mode using RADIUS tunnel attributes:

!The IKE configurations are as follows: crypto isakmp policy 1


!

! The IPsec configurations are as follows: crypto ipsec transform-set trans1 esp-3des esp-sha-hmac


!

! Initiate aggressive mode using Radius tunnel attributes crypto isakmp peer address 10.4.4.1

set aggressive-mode client-endpoint user-fqdn [email protected]

set aggressive-mode password cisco123

!

crypto map Testtag 10 ipsec-isakmp

set peer 10.4.4.1

set transform-set trans1

match address 101

!


ip address 10.5.5.1 255.255.255.0

crypto map Testtag

!


ip address 10.3.3.1 255.255.255.0

RADIUS User Profile Example

The following is an example of a user profile on a RADIUS server that supports the Tunnel-Client-

Endpoint and Tunnel-Password attributes: [email protected] Password = "cisco", Service-Type = Outbound

Tunnel-Medium-Type = :1:IP,

Tunnel-Type = :1:ESP,

Cisco:Avpair = "ipsec:tunnel-password=cisco123",

Cisco:Avpair = "ipsec:key-exchange=ike"


The following sections provide references related to the IKE: Initiate Aggressive Mode feature.


Related Topic

Security commands

Configuring authentication

Configuring IKE

Document Title


Configuring Authentication

Configuring Internet Key Exchange for IPsec VPNs

136



Feature Information for IKE Initiate Aggressive Mode

Standards

Standard Title


--

MIBs

MIB


MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS XE software releases, and feature sets, use Cisco MIB Locator found at the following URL: http://www.cisco.com/go/mibs

RFCs

RFC

• RFC 2409

• RFC 2868

Title

• RFC 2409, The Internet Key Exchange

• RFC 2868, RADIUS Attributes for Tunnel

Protocol Support




http://www.cisco.com/techsupport



Feeds.


Feature Information for IKE Initiate Aggressive Mode




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Table 8 Feature Information for IKE: Initiate Aggressive Mode

Feature Name

IKE: Initiate Aggressive Mode

Releases

Cisco IOS XE Release 2.1


The IKE: Initiate Aggressive

Mode feature allows you to specify RADIUS tunnel attributes for an IPsec peer and to initiate an

IKE aggressive mode negotiation with the tunnel attributes.

The following commands were introduced or modified: crypto

isakmp peer, set aggressive-

mode client-endpoint, set

aggressive-mode password.





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Internet Key Exchange for IPsec VPNs Configuration Guide Cisco IOS Release 12.4T

Internet Key Exchange for IPsec VPNs

Configuration Guide Cisco IOS Release

12.4T

Americas Headquarters

Cisco Systems, Inc.

170 West Tasman Drive

San Jose, CA 95134-1706

USA http://www.cisco.com

Tel: 408 526-4000

800 553-NETS (6387)

Fax: 408 527-0883

Configuring Internet Key Exchange for IPsec

VPNs

Finding Feature Information

Prerequisites for IKE Configuration

Restrictions for IKE Configuration

Information About Configuring IKE for IPsec VPNs

Supported Standards for Use with IKE

IKE Benefits

IKE Main Mode and Aggressive Mode

IKE Policies Security Parameters for IKE Negotiation

About IKE Policies

IKE Peers Agreeing Upon a Matching IKE Policy

IKE Authentication

RSA Signatures

RSA Encrypted Nonces

Preshared Keys

IKE Mode Configuration

How to Configure IKE for IPsec VPNs

Creating IKE Policies

◦ des--56-bit DES-CBC

◦ 3des--168-bit DES

◦ aes--128-bit AES

◦ aes 192--192-bit AES

◦ aes 256--256-bit AES

◦ rsa-sig--RSA signatures require that you configure your peer routers

◦ rsa-encr--RSA encrypted nonces require that you ensure each peer

◦ pre-share--Preshared keys require that you separately configure

◦ 1--768-bit DH

◦ 2--1024-bit DH

◦ 5--1536-bit DH

◦ 14--Specifies the 2048-bit DH group.

◦ 15--Specifies the 3072-bit DH group.

◦ 16--Specifies the 4096-bit DH group.

◦ 19--Specifies the 256-bit elliptic curve DH (ECDH) group.

◦ 20--Specifies the 384-bit ECDH group.

◦ 24--Specifies the 2048-bit DH/DSA group.

Troubleshooting Tips

What to Do Next

Configuring IKE Authentication

Configuring RSA Keys Manually for RSA Encrypted Nonces

Configuring Preshared Keys

◦ no-xauth--Prevents the router from prompting the peer for

Configuring IKE Mode Configuration

Configuring an IKE Crypto Map for IPsec SA Negotiation

◦ group1--768-bit DH

◦ group2--1024-bit DH

◦ group5--1536-bit DH

◦ group14--Specifies the 2048-bit DH group.

◦ group15--Specifies the 3072-bit DH group.

◦ group16--Specifies the 4096-bit DH group.

Configuration Examples for an IKE Configuration

Example: Creating IKE Policies

Example: Creating 3DES IKE Policies

Example: Creating an AES IKE Policy

Example: Configuring IKE Authentication

Where to Go Next

Additional References

Feature Information for Configuring IKE for IPsec VPNs

Call Admission Control for IKE

Finding Feature Information

Prerequisites for Call Admission Control for IKE

Information About Call Admission Control for IKE

IKE Session

Security Association Limit

Limit on Number of In-Negotiation IKE Connections

System Resource Usage

How to Configure Call Admission Control for IKE

Configuring the IKE Security Association Limit