Ubuntu – How to solve: “Connect to host some_hostname port 22: Connection timed out”

configurationopensshremote accessssh

I have two Ubuntu machines. Both have openssh-client and openssh-server installed on them. ssh-ing from machine G (fresh Ubuntu 11.10 installation) to machine K works great. But ssh-ing from machine K to machine G results always in the Error:

Connect to host some_hostname port 22: Connection timed out

I went through the troubleshooting section of help.ubuntu.com and I got the following results:

ps -A | grep sshd # results in
848 ?        00:00:00 sshd

–

sudo ss -lnp | grep sshd # results in
0   128   :::22   :::*   users:(("sshd",848,4))
0   128   *:22    *:*    users:(("sshd",848,3))

–

ssh -v localhost # works!

–

sudo ufw status verbose # yields: "Status: inactive"

I haven't changed anything in the config file. What can I do to locate the problem and solve it? I would appreciate any hint!

Edit:

ping was succesful in both directions!

I did a telnet <machineK> 22 from machine G which resulted in trying and then in telnet:

Unable to connect to remote host: Connection timed out.

But telnet the other way around worked just fine!

Edit 2:

ssh start/running, process 966 # yields: ssh start/running, process 966

/etc/hostname # contains my hostname, let's call it blubb
/etc/hosts # contains the following
127.0.0.1       localhost
# 127.0.1.1     blubb
129.26.68.74    blubb # I added this!

–

sudo service ufw status # yields: ufw start/running

I installed Gufw and set it to ON. Then I selected from Incoming the option ALLOW. Then I ssh'ed to another machine from where I ssh'ed back to my machine. Still the same error as above: connect to host blubb port 22: Connection timed out

Any more hints, what I can check?

Best Answer

So your machineG (the fresh install) is the one with issues:

  • Check sshd if it's up sudo service ssh status.
  • Check Name resolution. The name of your machine, check it if is the same on /etc/hostname, and /etc/hosts.
  • Check firewall. sudo service ufw status maybe is best if you install firewall of ubuntu Gufw.

hi! did you solve it? @philipballew asked you to see if you have port 22 enable.. do this on the 2 machines netstat -nat | grep 22: you will see something like this: 

~> netstat -nat | grep 22
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      
tcp        0      0 10.202.10.13:53414      173.194.76.125:5222     ESTABLISHED 
tcp        0      0 10.202.10.13:50912      10.100.202.21:22        TIME_WAIT   
tcp        0      0 :::22                   :::*                    LISTEN

If one of the ports 22 are not listen then re-check all that I previous told you. Actually I'm a bit lots with the names of the machines. You call them in differents names all the time....

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