Forum Discussion

Sergi0's avatar
Sergi0
Icon for Nimbostratus rankNimbostratus
Apr 02, 2018

GTM irule CNAME filter

I would like to create a filter on my GTM for remove CNAME and replace with the default answer like GTM bind does not have CNAME. I want to block respond CNAME I have "; dig cname www.wip.comp...
application delivery
BIG-IP DNS
devops
dns
gtm
irule
iRules
JG's avatar
JG
Icon for Cumulonimbus rankCumulonimbus
Apr 04, 2018

I'd try and find out why clients are sending this CNAME query to this server in the first place, which seems to suggest a DNS configuration error, and solve that problem. But specific to blocking the query type, here's one you could use:

when DNS_REQUEST {
    if { !([string toupper [DNS::question type]] eq "A") }  {
        DNS::last_act reject
        DNS::return
    }
}

.