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I have a strange problem and I'm not sure where to begin. My ssh client works on some servers but times out on others.

Obviously, I checked that the servers are accessible via ssh from other locations. From my machine A I can log on to C only by logging on to B first. There are at least two servers for which this is the case. To make matters more strange

  1. sudo ufw status -> Status: inactive
  2. nmap -sT -p 22 <problem_server> -> ...22/tcp open ssh...

On one affected server I am getting: ssh_exchange_identification: Connection closed by remote host and on the other I am getting ssh: connect to host <problem_server> port 22: Connection timed out

With both of these servers I can log in from other machines. How can I troubleshoot such a problem?

share|improve this question
Have you considered the possibility that there might problems in the routes from your Machine to the servers. Are the other machines you tried out in the same subnet as yours? – Hashken Dec 10 '12 at 11:32
Other machines from the same subnet can connect to the servers in question. – mmdanziger Dec 10 '12 at 11:35
Can you try ssh -vvvv …? It might also be worth to have a look at /etc/ssh/sshd_config. Does the both configs have differences and if yes, what are they? – qbi Feb 27 '13 at 6:34

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