Debian Bug report logs - #214741
postfix: $myhostname not reading the FQDN correctly

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Joe Nahmias <joe@nahmias.net>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: postfix: $myhostname not reading the FQDN correctly

Date: Wed, 08 Oct 2003 02:27:50 -0400

Package: postfix
Version: 2.0.16-1
Severity: normal

Hello,

It seems that there is a problem with how postfix gets the default $myhostname.
I get the following error in /var/log/mail.warn, even though my hostname is
properly configured:

Oct  8 01:05:17 laptop postfix/smtpd[3730]: warning: My hostname laptop is not a fully qualified name - set myhostname or mydomain in /etc/postfix/main.cf

Unfortunately, this caused all mail to get bounced as postfix thought that mail
for my domain was an attempt to relay...  I got a number of these messages
until I edited /etc/postfix/main.cf and manually set "mydomain = nahmias.net".

For reference, here is the configuration for my hostname:

/etc/hostname:
laptop

/etc/host.conf:
order hosts,bind
multi on

/etc/hosts:
127.0.0.1       laptop.nahmias.net laptop localhost


This seem to result in (an otherwise) correct and functional hostname
configuration:

joe@laptop:~ $ hostname --short
laptop
joe@laptop:~ $ hostname --domain
nahmias.net
joe@laptop:~ $ hostname --fqdn
laptop.nahmias.net

NB: The documentation for both hostname(1) and postfix *claim* to get the FQDN
from gethostname(2).  Something here is just not right.

Let me know if I can provide any further assistance,
Joe Nahmias


-- System Information:
Debian Release: testing/unstable
Architecture: i386
Kernel: Linux laptop 2.4.21-4-686 #1 Sat Aug 2 23:27:25 EST 2003 i686
Locale: LANG=C, LC_CTYPE=C

Versions of packages postfix depends on:
ii  adduser                       3.51       Add and remove users and groups
ii  debconf                       1.3.14     Debian configuration management sy
ii  dpkg                          1.10.15    Package maintenance system for Deb
ii  libc6                         2.3.2-8    GNU C Library: Shared libraries an
ii  libdb4.1                      4.1.25-6   Berkeley v4.1 Database Libraries [
ii  libgdbm3                      1.8.3-2    GNU dbm database routines (runtime
ii  netbase                       4.13       Basic TCP/IP networking system

-- debconf information:
* postfix/main_mailer_type: Internet Site
* postfix/append_dot_mydomain: false
  postfix/bad_recipient_delimiter: 
  postfix/rfc1035_violation: false
* postfix/chattr: true
  postfix/relayhost: 
  postfix/master_upgrade_warning: 
* postfix/mailname: nahmias.net
  postfix/mynetworks: 127.0.0.0/8
  postfix/transport_map_warning: 
* postfix/root_address: NONE
  postfix/recipient_delim: +
  postfix/mailbox_limit: 0
* postfix/destinations: $myhostname, localhost.$mydomain, $mydomain
  postfix/procmail: true
  postfix/dynamicmaps_upgrade_warning: 
  postfix/db_upgrade_warning: true
  postfix/not_configured: 

Message #10 received at 214741@bugs.debian.org (full text, mbox, reply):

From: Mike Paul <mike@wyzardry.net>

To: 214741@bugs.debian.org

Subject: More info on this bug

Date: Mon, 08 Oct 2007 23:10:30 -0400

[Message part 1 (text/plain, inline)]

Four years later (to the day, coincidentally), this bug still exists,
though in a slightly different form.  I've done some research and can
provide a bit more information.

If $myhostname isn't defined manually in the config file, Postfix uses
gethostname() to query the system's hostname.  $myhostname needs to be
an FQDN, though, so if the name returned by gethostname() doesn't
contain at least one dot, it appends the value of $mydomain if that's
defined in the config file, or else the static string "localdomain".

Notably, Postfix does *not* call gethostbyname() on the name returned by
gethostname(), the way the "hostname --fqdn" command does.

This'll work as expected if gethostname() returns an FQDN, but on a
typically-configured Debian system, it doesn't.  It returns a "short"
hostname, and this leads to Postfix using e.g. "foo.localdomain" as
$myhostname, even though "hostname --fqdn" returns "foo.bar.com".

Steps to reproduce:
      * Install a fresh copy of Debian (current release is etch).
      * When asked for the machine's hostname during installation, enter
        "foo".
      * When asked for the machine's domain name, enter "bar.com".
      * Install Postfix, and choose the default "Internet Site"
        configuration.  The "mail name" setting doesn't matter.
      * Remove the "myhostname = foo.bar.com" line
        from /etc/postfix/main.cf.  This line is put there by debconf,
        and it works around the problem, but it's redundant and
        shouldn't be necessary.  The machine already knows its FQDN, and
        the sensible default would be to use it.
      * Run "hostname --fqdn" and "hostname --domain".  They will return
        "foo.bar.com" and "bar.com" respectively, as expected.
      * Run "postconf myhostname" and "postconf mydomain".  They will
        return "foo.localdomain" and "localdomain" respectively.  This
        is wrong.

Postfix's behavior here suggests that the machine's hostname, as
returned by gethostname() (i.e. the "hostname" command, without the
"--fqdn" option) is supposed to be an FQDN.  But that isn't the case on
Debian, (nor on other common Linux distros AFAIK), and I don't see why
I'd want my system configured that way anyway.  There don't seem to be
any clear guidelines or best practices on this matter.

Since Postfix wants an FQDN for $myhostname, I think it should get the
default value in the same way the "hostname --fqdn" command does:  get
the (probably short) hostname using gethostname(), and then call
gethostbyname() on it to look up the FQDN.  It's still possible to get
something that isn't an FQDN on a misconfigured system, but at least the
behavior would be consistent with that of the well-known hostname tool,
and would work as expected with Debian's out-of-the-box configuration.

(As an aside, it's possible to get an FQDN hostname in Debian by typing
an FQDN into the hostname box during installation.  It contradicts the
instructions in that box, which say that "the hostname is a single
word", but the installer is smart enough to skip asking for the domain
name when an FQDN is entered as the hostname.  But this causes problems
of its own:  the Postfix Debconf stuff thinks the machine's FQDN is
"foo.bar.com.bar.com".)
-- 
Mike Paul <mike@wyzardry.net>

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Message #15 received at 214741@bugs.debian.org (full text, mbox, reply):

From: Harald Braumann <harry@unheit.net>

To: 399802@bugs.debian.org, 214741@bugs.debian.org

Subject: #399802 and #214741 the same?

Date: Fri, 4 Dec 2009 12:24:33 +0100

[Message part 1 (text/plain, inline)]

Hi,

aren't #399802 and #214741 the same? 

Cheers,
harry

PS: I'm not sure if I'm supposed to merge bugs in such a case or if
this is something that only the maintainers do.

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Message #22 received at 214741@bugs.debian.org (full text, mbox, reply):

From: Yann SOUBEYRAND <yann.soubeyrand@gmx.fr>

To: 214741@bugs.debian.org

Date: Mon, 05 Apr 2010 17:00:31 +0200

Hi!

This bug is still present in Postfix 2.6.5.

Message #27 received at 214741@bugs.debian.org (full text, mbox, reply):

From: Hristo Erinin <hristo.erinin@gmail.com>

To: 214741@bugs.debian.org

Subject: postfix: myhostname (if not set explicitly) is assigned the hostname with localdomain by default

Date: Mon, 11 Oct 2010 18:03:16 +0200

Hello,

This bug is still present after 7 years. A confirmation of the bug in 2.5.5-1.1:
Oct  6 12:27:27 fury postfix/postqueue[19564]: dict_eval: expand
$myhostname, localhost.$mydomain, localhost -> fury.localdomain,
localhost.localdomain, localhost
Oct  6 12:27:27 fury postfix/postqueue[19564]: dict_eval: expand
$myhostname -> fury.localdomain

The easiest workaround is setting $mydomain appropriately. This way
the hostname and domain is used by the daemon.

Also please note that the documentation for the package still falsely
claims if unspecified, by default myhostname is set to the FQDN of the
server.


-- 
Best Regards,
Hristo Erinin
System Administrator

Message #32 received at 214741@bugs.debian.org (full text, mbox, reply):

From: LaMont Jones <lamont@debian.org>

To: Hristo Erinin <hristo.erinin@gmail.com>, 214741@bugs.debian.org

Subject: Re: Bug#214741: postfix: myhostname (if not set explicitly) is assigned the hostname with localdomain by default

Date: Mon, 11 Oct 2010 11:36:33 -0600

On Mon, Oct 11, 2010 at 06:03:16PM +0200, Hristo Erinin wrote:
> Oct  6 12:27:27 fury postfix/postqueue[19564]: dict_eval: expand
> $myhostname -> fury.localdomain

What is the output from these commands?
    hostname --fqdn
    grep ^127 /etc/hosts

lamont

Message #37 received at 214741@bugs.debian.org (full text, mbox, reply):

From: Hristo Erinin <hristo.erinin@gmail.com>

To: 214741@bugs.debian.org

Subject: Re: Bug#214741: postfix: myhostname (if not set explicitly) is assigned the hostname with localdomain by default

Date: Tue, 12 Oct 2010 00:43:55 +0200

Hello,

On Mon, Oct 11, 2010 at 7:36 PM, LaMont Jones <lamont@debian.org> wrote:
> What is the output from these commands?
>    hostname --fqdn
feer@fury:~$ hostname --fqdn
fury.int.hellvetica.net


>    grep ^127 /etc/hosts
feer@fury:~$ grep ^127 /etc/hosts
127.0.0.1       localhost.localdomain           localhost

I've tried removing the localhost.localdomain from the line above but
it made no difference.

Thanks!

-- 
Best Regards,
Hristo Erinin

Message #42 received at 214741@bugs.debian.org (full text, mbox, reply):

From: Johnathon Tinsley <johnathon@positive-internet.com>

To: 214741@bugs.debian.org

Subject: Bug still a problem

Date: Wed, 05 Sep 2012 10:32:43 +0100

Just confirming, this is still a problem.

-- 
All postal correspondence to:
The Positive Internet Company, 24 Ganton Street, London. W1F 7QY

The Positive Internet Company Limited is registered in England and Wales.
Registered company number: 3673639. VAT no: 726 7072 28.
Registered office: Northside House, Mount Pleasant, Barnet, Herts, EN4 9EE.

Message #47 received at 214741@bugs.debian.org (full text, mbox, reply):

From: Jonathan Hall <flimzy@flimzy.com>

To: 214741@bugs.debian.org

Subject: Patch for 214741

Date: Tue, 29 Oct 2013 07:42:04 -0500

[Message part 1 (text/plain, inline)]

We are also experiencing this with postfix 2.7.1 and 2.9.6.  The 
included patch solves the problem for 2.7.1, and should be trivial to 
adapt for newer versions.

[214741.patch (text/x-patch, attachment)]

Message #52 received at 214741@bugs.debian.org (full text, mbox, reply):

From: Jonathan Hall <flimzy@flimzy.com>

To: 214741@bugs.debian.org

Subject: Also happens in postfix 2.10.2; patch

Date: Wed, 30 Oct 2013 10:11:31 -0500

[Message part 1 (text/plain, inline)]

Tags: patch

I have also confirmed this bug to exist in postfix 2.10.2, and have 
adapted my previous patch to work with this version.

[2.10.2_214741.patch (text/x-patch, attachment)]

Message #89 received at 214741-close@bugs.debian.org (full text, mbox, reply):

From: LaMont Jones <lamont@debian.org>

To: 214741-close@bugs.debian.org

Subject: Bug#214741: fixed in postfix 2.11.1-1

Date: Mon, 16 Jun 2014 15:56:45 +0000

Source: postfix
Source-Version: 2.11.1-1

We believe that the bug you reported is fixed in the latest version of
postfix, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 214741@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
LaMont Jones <lamont@debian.org> (supplier of updated postfix package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)


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Hash: SHA1

Format: 1.8
Date: Sat, 07 Jun 2014 08:48:54 +0100
Source: postfix
Binary: postfix postfix-ldap postfix-cdb postfix-pcre postfix-mysql postfix-pgsql postfix-dev postfix-doc
Architecture: all i386 source
Version: 2.11.1-1
Distribution: unstable
Urgency: medium
Maintainer: LaMont Jones <lamont@debian.org>
Changed-By: LaMont Jones <lamont@debian.org>
Closes: 214741 730848 733123 738314 750485
Description: 
 postfix-cdb - CDB map support for Postfix
 postfix-dev - Loadable modules development environment for Postfix
 postfix-doc - Documentation for Postfix
 postfix    - High-performance mail transport agent
 postfix-ldap - LDAP map support for Postfix
 postfix-mysql - MySQL map support for Postfix
 postfix-pcre - PCRE map support for Postfix
 postfix-pgsql - PostgreSQL map support for Postfix
Changes:
 postfix (2.11.1-1) unstable; urgency=medium
 .
   [LaMont Jones]
 .
   * fix usage of LIBLIST in init.d.  Closes: #733123
 .
   [Tanguy Ortolo]
 .
   * copy /etc/host.conf to the chroot
 .
   [Guilhem Moulin]
 .
   * Build dict_ldap.so with SASL binding enabled.  Closes: #730848
 .
   [Joey Hess]
 .
   * Fix short description in init script.  Closes: #738314
 .
   [Jonathan Hall]
 .
   * Better myhostname default handling.  Closes: #214741
 .
   [Wietse Venema]
 .
   * New Upstream release.  Closes: #750485
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