Postfix suddenly broke for unaccountable reason

[Vlado Plaga]

Hello Ubuntu users!

I'm not sure where this comes from, but yesterday I noticed that postfix
had not delivered any of my outgoing e-mails for six days. Possibly I've
made an apt-get dist-upgrade around that time. This is what
/var/log/mail.err* contains:

Dec 12 15:47:00 platypus postfix/master[4805]: fatal: /etc/postfix/master.cf: line 84: bad hostname or network address: ::1
Dec 12 17:35:53 platypus postfix/postfix-script: fatal: the Postfix mail system is not running
Dec 12 22:46:54 platypus postfix/master[4733]: fatal: /etc/postfix/master.cf: line 84: bad hostname or network address: ::1
Dec 13 00:21:07 platypus postfix/postfix-script: fatal: the Postfix mail system is not running
Dec 13 16:18:55 platypus postfix/master[4738]: fatal: /etc/postfix/master.cf: line 84: bad hostname or network address: ::1

[... and so on for every reboot...]

But the interesting thing is that the /etc/postfix/master.cf's file date
was 2004-11-13 - long before the problem occured. Also, I don't think I
ever changed anything in that file on my own.

Now looking for a solution I found this site:

http://www.linuxnotes.net/wiki.pl?PostfixServer

It proposes to uncomment the following line in the abovementioned
master.cf:

  ::1:smtp       inet n   -       -       -       -       smtpd

This indeed caused postfix to deliver all pending eMails, as I could see
in /var/log/mail.log

I first though about reporting this at https://bugzilla.ubuntu.com/ but
maybe it is better to ask whether others made similar experiences or
know where this might have come from.

Regards,

  Vlado