GTM iRule to forward dns request to a pool of DNS servers

Hi KingMeow,

to simplify the iRule above the conditions can be combined, i.e. as follows:

when DNS_REQUEST {
    if {[IP::addr [IP::client_addr] equals 10.10.10.10/32] and ([string tolower [DNS::question name]] ends_with "xyz.domain.com")} {
        log local0. "dns query <[DNS::question name]> from local network: <[IP::client_addr]>"
        DNS::disable gtm
    }
}

(To verify the query name a comparison can be done by "ends_with", "equals", "starts_with" or "contains".)

Btw, there are two alternative methods for GTM to achieve a similar behavior as settings scopes on a DNS server.

The topology based method allows definition of regions and map them to available resources.

A way to configure them is described in this post "Topology LB - Not allow Wide IP to resolve to Internet".

The second method would be a similar rule as above in the context of the WideIP to pick a GTM-pool containing the internal resource records.

In both cases it would be necessary to monitor the internal real servers by the GTM controller.

Thanks, Stephan