SSH doesn't start

Question

Here is what I see in syslog

Sep 18 01:01:16 homepage init: ssh main process ended, respawning
Sep 18 01:01:16 homepage init: ssh main process (1444) terminated with status 255
Sep 18 01:01:16 homepage init: ssh main process ended, respawning
Sep 18 01:01:16 homepage init: ssh main process (1447) terminated with status 255
Sep 18 01:01:16 homepage init: ssh main process ended, respawning
Sep 18 01:01:16 homepage init: ssh main process (1450) terminated with status 255
Sep 18 01:01:16 homepage init: ssh respawning too fast, stopped

The port in sshd_config is 22, ListenAddress is commented

I got it when I tried to move ssh from 22 to 2222 port. Got it not worked and changed back, but with no luck.

Any ideas?

UPD:

I have no idea why it helped, but I just replaced sshd_config with one from backup. According to diff they were identical (didn't check md5sum though). And this helped :-S

UPD2:

it is 5.8p1-1ubuntu3

Answer 1

Judging from the fact that you are using Ubuntu, this seems te be a bug, as also indicated by the answers to this question on AskUbuntu.com:

Quoting original answer:

This appears to be the result of bug #687535, which was fixed recently in natty, and has been uploaded to both maverick and lucid as a proposed update.

https://bugs.launchpad.net/ubuntu/lucid/+source/openssh/+bug/687535

I'd encourage everyone to go there, try the test case (search for TEST CASE), and post your results both before and after installing the proposed fix. That will help the SRU team decide that verification has been done and release it as an update.

Additionally, there seems to be at least one other person who has experienced the same problem and has successfully solved it by commenting the specific ListenAddress directive and adding a generic ListenAddress 0.0.0.0, as described in this blog post:

[....]

My thinking is that sshd was trying to start up before the network interfaces were configured, which was causing it to fail as it had a ListenAddress directive in /etc/ssh/sshd_config.

Commenting out the specific ListenAddress directive and adding ListenAddress 0.0.0.0 to let sshd listen on any address solved the problem. The fileserver has only 1 IP address anyway.

Answer 2

Make sure you don't have sshd daemons running in the system

ps -ef | grep sshd

Kill any if there are.

Also make sure that no other process uses port 22

netstat -an | grep 22 | grep LISTEN

Then start sshd again (depends on system or distro you are using)