Demi Marie Obenour wrote in
<6baaf997-0462-f5de-402b-c77f01ff5...@gmail.com>:
|On 12/2/22 08:08, David Dolan wrote:
|> On Fri, 2 Dec 2022 at 10:33, David Dolan <daithido...@gmail.com> wrote:
|>> Subject: Re: helo command rejected
|>>> From: Viktor Dukhovni <postfix-users () dukhovni ! org>
|>>> Date: 2022-12-01 16:56:13
|>>> Message-ID: Y4jcrRxsEJPsWZVZ () straasha ! imrryr ! org
...
|>>> Indeed the hostname "wx-use2.prod.hydra.sophos.com" exists and has
|>>> multiple IP addresses, requiring support for either TCP or EDNS with a
|>>> UDP buffer larger than 512 bytes Perhaps your DNS resolver or the C
|>>> library stub resolver are configured to limit DNS to 512 bytes of UDP
|>>> and also don't retry over TCP? In that case you'd get only a truncated
|>>> response with no answers, and have no way to recover:
...
|>>> Are you on a MUSL libc system? IIRC there's no support for TCP in
|>>> MUSL's stub resolver. See, for example:
...
|> I guess it's using the musl resolver in Alpine so we need to migrate \
|> OS to
|> get past this issue?
|
|Another option would be for Postfix to use an alternate DNS library, like
|C-Ares, libasr, or libunbound.
it now has EDNS and TCP:
Author: Rich Felker <dal...@aerifal.cx>
AuthorDate: 2022-09-25 22:48:12 -0400
Commit: Rich Felker <dal...@aerifal.cx>
CommitDate: 2022-10-19 14:01:31 -0400
dns query core: detect udp truncation at recv time
commit 51d4669fb97782f6a66606da852b5afd49a08001
Author: Rich Felker <dal...@aerifal.cx>
AuthorDate: 2022-09-22 14:17:05 -0400
Commit: Rich Felker <dal...@aerifal.cx>
CommitDate: 2022-09-22 14:17:05 -0400
dns: implement tcp fallback in __res_msend query core
--steffen
|
|Der Kragenbaer, The moon bear,
|der holt sich munter he cheerfully and one by one
|einen nach dem anderen runter wa.ks himself off
|(By Robert Gernhardt)
