Bug 509844

Summary:	mail-mta/postfix-2.10.3: default hostname is wrong
Product:	Gentoo Linux	Reporter:	Sven <sven.koehler>
Component:	Current packages	Assignee:	Eray Aslan <eras>
Status:	UNCONFIRMED ---
Severity:	normal	CC:	gentoo_bugs_peep, net-mail+disabled, williamh
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description Sven 2014-05-08 12:59:36 UTC

The whole problem is described here:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=214741

PostFix uses the value returned by gethostname() as the default hostname. Since that value is not a fully qualified hostname, postfix then adds ".localdomain" to the end.

So even on systems where $(hostname -f) returns the right thing, postfix will use $(hostname -s).localdomain as the default hostname. Postfix seems to be simply broken in that regard.

The Gentoo ebuilds don't seem to apply the patch that is available for this problem (see the URL above). IMHO they should.

The obvious workaround is to set the hostname explicitly in postfix's config. But that shouldn't be necessary.

Reproducible: Always

Comment 1 Philippe Chaintreuil 2019-03-27 13:28:10 UTC

For informational purposes, here's upstream's response to such changes:

http://postfix.1071664.n5.nabble.com/Automatically-substitute-FQDN-of-local-system-in-config-td90055.html#none

TL;DR: "hostname -f" isn't stable without a network or with a changing network (eg: laptop) therefore they believe it will break mail delivery on such systems.  This is why they append the .localdomain on gethostname() values returned without a dot.