Forum Discussion

eric_haupt1's avatar
eric_haupt1
Icon for Nimbostratus rankNimbostratus
Sep 26, 2017

GTM - Pool selection based on forward lookup zone

I'm just throwing this out there to see if this is even possible before I spend time working on a solution. We have devised various DNS pools - each pool has monitors with various forward lookup zones being checked using DNS health monitoring. The pools are set to fail any node that does not report all health monitors active. We then use pool select code in an irule to direct DNS within our infrastructure to various points based on the ability of the node DNS servers to provide certain levels of DNS robustness. This ensure our clients always go to the best pool - the pool that can offer the most ability based on a forward lookup zone perspective. This works very well for us, but I'd like to take it to the next level and also configure conditional checking. For example: if our local pool can resolve all forward lookup zones except .com - then we pool select a secondary datacenter for DNS. This is a coarse failover - ideally I want to only forward queries for *.com to the secondary datacenter DNS servers and keep everything else (from a forward lookup perspective) local.

 

1 Reply

  • Hi,

    you can create a DNS SERVERS pool dedicated for

    *.com
    requests and assign to it monitors checking , google.com, microsoft.com ...

    and use an irule like that assigned to the DNS VS:

    when DNS_REQUEST {
        switch -glob -- [DNS::question name] {
            "*.com" {pool P_FORWARD_ZONE_COM}
            "*.org" {pool P_FORWARD_ZONE_ORG}
            default {pool P_FORWARD_ZONE_DEFAULT}
        }
    }