my DNS irule - how can i optimise it further or is there a better way?

Awesome thanks Aaron.

I've tried your suggestion of

if { [set FakeIPv4 [class match -value -- $fqdn equals site1_whitelist]] ne ""} {

but i get response is not well formed XML, i have tried altering it a bit but i honestly can't see whats wrong. interestingly even if I comment the line out it still displays the error until i remove it completely.

I had the same thoughts about a single site subnet list, but couldn't work out how I'd link both the comparison of address and site name in one if condition. but i suppose would you do something like this (in sudo code)?

if { [class match [IP::client_addr] equals site_subnet_list_all && [class match -value [IP::client_addr] equals site_subnet_list_all] eq "site1" ] }

many thanks for your response btw.

Regards

Adrian