FORMERR - automatically retried?

[George (Yorgos) Thessalonikefs]

Hi John,

For upstream traffic, on FORMERR responses, Unbound will retry without 
EDNS if an EDNS query was previously sent.

But from your log output these queries and replies seem to be for the 
downstream (client facing) traffic.

I deduce that
     log-queries: yes
     log-replies: yes
     log-tag-queryreply: yes
is part of your configuration.

Then what you see is Unbound receiving a query from 10.121.16.73 for 
collector.newrelic.com. A IN and sending back a FORMERR reply. This 
FORMERR reply came from Unbound itself indicating that there is 
something wrong with the query.
There is nothing to retry in this case, the client needs to send a 
correct DNS query.

Best regards,
-- Yorgos

On 12/08/2023 20:09, John Horne via Unbound-users wrote:
> Hello,
> 
> We are running Unbound 1.16 on a Rocky 9 Linux server, and I'm trying to see
> why some DNS lookups are intermittently failing. It seems to be that the
> FORMERR code is being returned, probably due to EDNS being specified.
> 
> My question is does Unbound disable EDNS and retry requests which return a
> FORMERR error? I gather that this is done by some DNS software, but am unsure
> if Unbound does this.
> 
> Looking at the Unbound logs shows (for example):
> 
> Aug 11 22:31:35 unbound[944:0] query: 10.121.16.73 collector.newrelic.com. A IN
> Aug 11 22:31:35 unbound[944:0] reply: 10.121.16.73 - - - FORMERR - - -
> 
> There is no logged retry for the request, so I am assuming that Unbound does
> not retry requests after a FORMERR error.
> 
> 
> 
> Thanks,
> 
> John.
> 
> --
> John Horne | Senior Operations Analyst | Technology and Information Services
> University of Plymouth | Drake Circus | Plymouth | Devon | PL4 8AA | UK
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