Configure Web servers for MAC forwarding

When using MAC forwarding with Load Balancer, traffic for all ports is routed through the primary Load Balancer. Requests will therefore carry the Load Balancer cluster IP address as destination. To be able to handle these requests, the Web servers need to be configured as follows.

On AIX, the loopback interface is aliased using the ifconfig command. For Web server node 1 in our scenario, the command is issued as follows:

# ifconfig lo0 alias 9.26.126.103 netmask 255.255.255.255

Important: Make sure you use the netmask option with the netmask 255.255.255.255 when you are adding an IP alias to the loopback device in AIX. If you use an incorrect netmask, or do not use this option at all. A new route will be added to your routing table using the loopback as the gateway, which causes routing problems.

Add this command to the end of the /etc/rc.net file so that it will be run every time the networking configuration is run (for example, after a system reboot).

For examples of how to set up the loopback alias on other operating systems, refer to the Load Balancer Administration Guide, GC31-6858. In any case, after adding the alias, check for extra routes that may have been created, and remove them according to the correct procedure for each operating system.
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