by tsightler » Fri Apr 20, 2012 7:40 pm people like this post
It's simple network mapping, so the last digit would always be the same. For example, if you had a network that was 10.1.1.0/24 and a failover network that was 10.2.2.0/24, then the rule would simply be "10.1.1.D" -> "10.2.2.D" and thus any IP address that started with 10.1.1.X would be replaced with 10.2.2.X, with the X remaining the same.
Of course, if you have IP addresses that are already used in the remote site, then you will need to specify individual IP addresses, but this becomes a large burden for more than a small number of systems. Typically it is easier to simply create a "failover network" on the remote site and map all IP addresses from one site to the other network with a single rule.