[Pdns-users] Recursor - custom TTL for particular domain

Xan Charbonnet xan at charbonnet.com
Thu Sep 14 14:26:55 UTC 2023

Hello all,

I'm setting up an instance of the PowerDNS Recursor.  I would like to 
override the TTL for particular queries of particular domains: I need 
any CNAME from one particular domain to have an overridden, very low TTL.

I wrote a Lua script which does this via "postresolve", however, it only 
works halfway.  It succeeds in getting clients to see the low TTL.  But 
what I also need is for the Recursor to honor this lower TTL when it 
decides whether or not to check for updates.

I've experimented with "preresolve" but I don't seem to be finding any 
way to modify the returned query, as that executes before the query 
takes place.  And nothing I do in "postresolve" affects the Recursor's 
/internal/ opinion of the TTL.  Basically, preresolve is too early and 
postresolve is too late.

If anyone can think of a way to get the Recursor to behave this way, I 
would appreciate it.  Thanks.


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