[Pdns-users] Recursor and LUA scripting: I don't understand why preresolve answering a CNAME won't cascade to other records

[Oscar Koeroo]

Yes! This worked as expected. I assumed it was a designed choice, and it seemed it was.
Thank you Bert and Roman for these quick answers.


Oscar Koeroo



> On 31 May 2020, at 12:14, bert hubert <bert.hubert at powerdns.com> wrote:
> 
> On Sun, May 31, 2020 at 12:08:36PM +0200, Oscar Koeroo via Pdns-users wrote:
> 
>> I’m using the following LUA script to intercept, but I don’t understand
>> the results.  Why doesn’t the dig get the CNAME to got to the A record I
>> have in my domain.local zone?  I expected dig to try to get the CNAME
>> value of qr.domain.net and the CNAME value of that result, which seems to
>> halt there.
> 
> Hi Oscar!
> 
> So firstly, a resolver is expected to provide a complete answer. If it
> supplies only a CNAME, a client can assume there is nothing more. A
> stub-resolver won't itself recurse.
> 
>> The expected result I was looking for was:
> 
> The good news is, we thought of this scenario, and we have this:
> 
> "CNAME chain resolution
> 
> It may be useful to return a CNAME record for Lua, and then have the
> PowerDNS Recursor continue resolving that CNAME.  This can be achieved by
> setting dq.followupFunction to followCNAMERecords and dq.followupDomain to
> “www.powerdns.com”.  PowerDNS will do the rest.  "
> 
> https://doc.powerdns.com/recursor/lua-scripting/hooks.html#cname-chain-resolution
> 
> Good luck!
> 
> 	Bert