Configuring broadcast relay. Avaya Media Gateway G350, Media Gateway G250

Configuring the router

Table 128: DHCP server CLI commands (continued)

Root level command ip dhcp-server show ip dhcp-server bindings show ip dhcp-server statistics

First level command

Second level command

Description

Activate DHCP server

Display bindings

Display DHCP server statistic

3 of 3

Configuring broadcast relay

When you configure broadcast relay, the router forwards broadcast packets across interfaces.

You can configure broadcast relay types including directed broadcast forwarding, NetBIOS rebroadcast, and DHCP and BOOTP client broadcast.

For more information about DHCP and BOOTP client broadcast, see

Configuring DHCP and

BOOTP relay on page 511.

Directed broadcast forwarding

A directed broadcast is an IP packet whose destination address is the broadcast address of a network or subnet. A directed broadcast causes every host on the network to respond. You can use directed broadcasts to obtain a list of all active hosts on the network. A hostile user can exploit directed broadcasts to launch a denial-of-service attack on the network. For each interface on the Avaya G250/G350 Media Gateway, you can configure whether the G250/G350 forwards directed broadcast packets to the network address or subnet mask address of the interface.

Enter ip directed-broadcast to enable directed broadcast forwarding on an interface. Use the no form of this command to disable directed broadcast forwarding on an interface.

524 Administration for the Avaya G250 and Avaya G350 Media Gateways

Configuring broadcast relay

NetBIOS rebroadcast

Network Basic Input Output System (NetBIOS) is a protocol for sharing resources among desktop computers on a LAN. You can configure the Avaya G250/G350 Media Gateway to relay

NetBIOS UDP broadcast packets. This feature is used for applications such as WINS that use broadcast but might need to communicate with stations on other subnetworks or VLANs.

Configuration is performed on a per-interface basis. A NetBIOS broadcast packet arrives from an interface on which NetBIOS rebroadcast is enabled. The packet is distributed to all other interfaces configured to rebroadcast NetBIOS.

If the NetBIOS packet is a net-directed broadcast, for example, 149.49.255.255, the packet is relayed to all other interfaces on the list, and the IP destination of the packet is replaced by the appropriate interface broadcast address.

If the NetBIOS broadcast packet is a limited broadcast, for example, 255.255.255.255, it is relayed to all VLANs on which there are NetBIOS-enabled interfaces. In that case, the destination IP address remains the limited broadcast address.

Enter ip netbios-rebroadcast both to enable NetBIOS rebroadcasts on an interface.

Enter ip netbios-rebroadcast disable to disable NetBIOS rebroadcasts on an interface.

Summary of broadcast relay commands

For more information about these commands, see Avaya G250 and Avaya G350 CLI

Reference, 03-300437.

Table 129: Broadcast relay CLI commands

Root level command Command interface

(dialer| fastethernet| serial|tunnel| vlan)

Description

Enter the Dialer, FastEthernet, Serial,

Tunnel

, or VLAN interface context

ip directed-broadcast ip netbios-rebroadcast

Enable or disable directed broadcast forwarding on the interface

Enable or disable NetBIOS rebroadcasts on the interface

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