Comment 7 for bug 377571

I think this might be a vaild issue under some circumstances but there is an easy workaround. I looks like the issue with #5 is that he didn't put a space between cat and the file path. I have the same issue with a fresh install and default settings.

The issue is that for a default install, the installer grabs the full comcast domain and puts that with a trailing dot in the /etc/hosts (not sure if that's valid or not) and then by default the postfix package grabs that hostname as the mail hostname.

Here is the output for me:

gitadmin@ubuntu:~$ postconf myhostname
myhostname = ubuntu.hsd1.il.comcast.net.
gitadmin@ubuntu:~$ cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 ubuntu.hsd1.il.comcast.net. ubuntu

# The following lines are desirable for IPv6 capable hosts
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
gitadmin@ubuntu:~$ cat /etc/hostname
ubuntu

FIX:

Removing the trailing dot from the myhostname entry in /etc/postfix/main.cf fixes the issue for me.