sshd seems to be run multiple times at startup

 it's with gutsy

Mindbogglingly unlikely to be an Upstart bug

Not an upstream bug for sysvinit

Could I see the output of this command, please?

  ls -l /etc/rc*.d/*ssh*

sure.

ls -l /etc/rc*.d/*ssh*
lrwxrwxrwx 1 root root 13 2007-11-25 15:25 /etc/rc1.d/K84ssh -> ../init.d/ssh
lrwxrwxrwx 1 root root 13 2007-11-25 15:25 /etc/rc2.d/S16ssh -> ../init.d/ssh
lrwxrwxrwx 1 root root 13 2007-11-25 15:25 /etc/rc3.d/S16ssh -> ../init.d/ssh
lrwxrwxrwx 1 root root 13 2007-11-25 15:25 /etc/rc4.d/S16ssh -> ../init.d/ssh
lrwxrwxrwx 1 root root 13 2007-11-25 15:25 /etc/rc5.d/S16ssh -> ../init.d/ssh

I'm not sure, but I think I have reinstalled from scratch since the intial bug report. But I checked, I still get this in the log at every boot:
Feb 28 11:12:00 xbx-laptop sshd[5368]: Server listening on :: port 22.
Feb 28 11:12:01 xbx-laptop sshd[5368]: error: Bind to port 22 on 0.0.0.0 failed: Address already in use.

but no longer
"ssh-agent[5797]: error: Unknown message 252" nor "Received SIGHUP; restarting."

I found this fix elsewhere.

Open /etc/ssh/sshd_config for editing. Uncomment the listening address for 0.0.0.0.

# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0

Change to:

# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
ListenAddress 0.0.0.0

I'm not sure why this needs to be done. I've got a number of Ubuntu/Debian machines and this was the first time I came across this problem. It was with Ubuntu 8.04 Beta.

Sorry. After making the change I mentioned above, you'll need to restart the server.

sudo /etc/init.d/ssh restart

@xbx:

Do you happen to know if you're on an ipv4 or an ipv6 network?

If you're an ipv4 network, try disabling ipv6 and enabling ipv4 listening in your /etc/ssh/sshd_config:
    #ListenAddress ::
    ListenAddress 0.0.0.0

Alternatively, if you're on an ipv6 network, try disabling ipv4 and enabling ipv6:
    ListenAddress ::
    #ListenAddress 0.0.0.0

Note this thread on the Fedora Forums:
   http://www.fedoraforum.org/forum/archive/index.php/t-26887.html

@xbx:

There are two separate issues.

First, the default setup is noisy : both ipv4 and ipv6 are configured on the network interface, and without a ListenAddress sshd will try to bind both, resulting in the "Address already in use" message.

Second, everytime the network interface goes up (say, you finally get your ipv4 address from your DHCP server), if-up restarts sshd (the "SIGHUP" message) to let it pick up that new interface.

Are you using DHCP ?

yes, I'm using dhcp (with a wifi connection), with ipv4

I just checked the log, and the error is still there.
But sshd works perfectly, it's just a log line that looks odd...
I actually don't remember why I filled this bug. I guess I was
looking for some other issue at the time, and stumbled upon this...

and uncommenting the line "ListenAddress 0.0.0.0" in /etc/ssh/sshd_config:

   #ListenAddress ::
   ListenAddress 0.0.0.0

fixes the issue.

This was http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=439661, fixed in OpenSSH 5.1p1; your workarounds with ListenAddress are fine for now, or I think most systems can just ignore this error.