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Forum Discussion

Livius's avatar
Livius
Icon for Cirrus rankCirrus
May 31, 2018

Extract the IP address in iRule from ADDITIONAL SECTION response in DNS query

Hi,   I have a piece of code in iRule triggering a DNS query on a VS as follows :   set original_fqdn [findstr $RouteValue "sip:N" 4 ";"] if {$static::debug} {log local0.info "fqdn =...
application delivery
BIG-IP
BIG-IP DNS
Leonardo_Souza's avatar
Leonardo_Souza
Icon for Cirrocumulus rankCirrocumulus
Jun 04, 2018

The lindex just gets an element from a list, starting from 0. Dump the variable resolved_ip to the logs and look what is inside of the list.

 

If the addition section is not on the list, just get the name, and make another query for a A record. Is not efficient, as you are doing 2 queries, but works. The information in the additional section is to avoid systems to have to do a second query, but if you can't do that with RESOLV::lookup, that is a valid option.