User Manual Peplink Balance Multi

USER MANUAL

Peplink Balance Series

11.3 WAN Health Check

To ensure traffic is routed to healthy WAN connections only, Peplink Balance provides the functionality to periodically check the health of each WAN connection.

The Health Check settings for each WAN connection can be independently configured via Network >

Interfaces > WAN > Health Check Settings

Enable the Health Check Settings by drop down to PING, DNS Lookup or HTTP

Method

Health Check Settings

This setting specifies the health check method for the WAN connection. The value of

Method can be configured as Disabled, Ping or DNS Lookup. The default method is DNS

Lookup. For Mobile Internet connection, the value of Method can be configured as

Disabled or SmartCheck.

Health Check Disabled

When Disabled is chosen in the Method field, the WAN connection will always be considered as up. The connection will NOT be treated as down in the event of IP routing errors.

Health Check Method: Ping

The ICMP PING packets will be issued to test the connectivity with a configurable target IP address or host name.

A WAN connection is considered as up if PING responses are received from either one or both of the PING Hosts.

PING Hosts

This setting specifies IP addresses or host names with which connectivity is to be tested via

ICMP Ping.

If Use first two DNS servers as Ping Hosts is checked, the target PING Host will be the first DNS server for the corresponding WAN connection.

Reliable PING hosts with a high uptime should be considered.

By default, the first two DNS servers of the WAN connection are used as the PING Hosts.

Health Check Method: DNS Lookup http://www.peplink.com

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DNS lookups will be issued to test the connectivity with target DNS servers. The connection will be treated as up if

DNS responses are received from either one or both of the servers, regardless of whether the result was positive or negative.

Health Check DNS

Servers

This field allows you to specify two DNS hosts’ IP address with which connectivity is to be tested via DNS Lookup.

If Use first two DNS servers as Health Check DNS Servers is checked, the first two DNS servers will be the DNS lookup targets for checking a connection's health. If the box is not checked, field Host 1 must be filled and field Host 2 is optional.

If the box Include public DNS servers is selected and no response is received from all specified DNS servers, DNS lookups will also be issued to some public DNS servers. A

WAN connection will be treated as down only if there is also no response received from the public DNS servers.

Connections will be considered up if DNS responses are received from any one of the health check DNS servers, regardless of a positive or negative result.

By default, the first two DNS servers of the WAN connection are used as the Health Check

DNS Servers.

Health Check Method: HTTP

HTTP connections will be issued to test the connectivity with configurable URLs and strings to match.

URL 1

WAN Settings > WAN Edit > Health Check Settings > URL 1

The URL will be retrieved when performing an HTTP health check. When String to Match is left blank, a health check will pass if the HTTP return code is between 200 and 299 (Note:

HTTP redirection codes 301 or 302 are treated as failures). When String to Match is filled, a health check will pass if the HTTP return code is between 200 and 299 and if the HTTP response content contains the string.

URL 2

WAN Settings > WAN Edit > Health Check Settings > URL 2

If URL 2 is also provided, a health check will pass if either one of the tests passed.

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Other Health Check Settings

Timeout

This setting specifies the timeout, in seconds, for ping/DNS lookup requests. Default

Timeout is set to 5 seconds.

Health Check

Interval

This setting specifies the time interval, in seconds, between ping or DNS lookup requests.

Default Health Check Interval is 5 seconds.

Health Check

Retries

This setting specifies the number of consecutive ping/DNS lookup timeouts after which

Peplink Balance is to treat the corresponding WAN connection as down. Default Health

Retries is set to 3.

For example, with the default Health Retries setting of 3, after consecutive 3 timeouts, the corresponding WAN connection will be treated as down.

Recovery Retries

This setting specifies the number of consecutive successful ping/DNS lookup responses that must be received before Peplink Balance treats a previously down WAN connection to be up again.

By default, Recover Times is set to 3. For example, a WAN connection that is treated as down will be considered to be up again upon receiving 3 consecutive successful ping/DNS lookup responses.

Note

In case a WAN connection goes down, all of the WAN connections with non-Always-on Connection Type will also be brought up until any one of higher priority WAN connections is up and found to be healthy. This design could increase the overall network availability.

For example, if WAN1, WAN2 and WAN3 have the connection types of Always-on, Backup Priority Group 1 and

Backup Priority Group 2 respectively, when WAN1 goes down, WAN2 and WAN3 will also try to connect. If WAN3 is connected first, WAN2 will still be kept connecting. If WAN2 is connected, WAN3 will disconnect or abort making connection.

Automatic Public DNS Server Check on DNS Test Failure

In case the health check method is set to DNS Lookup and checks failed, the Balance will automatically perform

DNS lookups on some public DNS servers. If the tests are success, it means the WAN may not be down but rather the target DNS server became malfunctioned. You will see the following warning message on the Main page.

http://www.peplink.com

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