[dns-operations] Retrying with TCP on timeout?

Anand Buddhdev anandb at ripe.net
Fri Apr 20 11:33:54 UTC 2018

On 20/04/2018 12:51, Stephane Bortzmeyer wrote:

Hi Stéphane,

> DNS resolvers retry with TCP when they receive a response with the TC
> (truncated) bit. But when the authoritative name servers timeout?
> Use case: the two authoritative name servers for .pf no longer reply
> over UDP, only TCP. Apparently, no resolver (I tried several, plus
> the RIPE Atlas probes) retry with TCP.

This breakage of .PF is unusual, and I don't think it deserves any
special treatment. And certainly not retrying over TCP. Adding more and
more workarounds to software for every new case of breakage is just a
very bad idea.


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