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Forum Discussion

shashank_shetti's avatar
shashank_shetti
Icon for Nimbostratus rankNimbostratus
Feb 17, 2016

RESOLV::lookup hard coded DNS ip address - How to avoid hard coding in irule

Here is the my irule code in how I resolve the ip address of domain name   set dest [lindex [RESOLV::lookup @10.10.100.100 -a "someSite.net"] 0]   I do not want to hard code the dns ip address...
application delivery
BIG-IP DNS
iRules
Kai_Wilke's avatar
Kai_Wilke
Icon for MVP rankMVP
Feb 18, 2016

Hi Shashank shetti,

you have to follow the workaround of SOL12224 (aka. 

recursion yes
) to allow the iRule to use the local BIND to ask recursive DNS queries.

https://support.f5.com/kb/en-us/solutions/public/12000/200/sol12224

Note: Alternatively, you may want to hardcode a generic virtual server name (e.g. VS_EXT_DNS or DNS_INT_DNS) into your iRule and then use the names virtual servers to access some internal/external DNS pools. This technique allows you to still have flexibility in the case the DNS server pools members require changes, but also have the option to use different DNS server pools (Internal/External) to launch the query.

Cheers, Kai