Hi everyone,
Energy was interrupted after a blackout and since then I can't connect remotely to a server. (CentOS 6).
The ssh service is running, as I have physically access.
I don't know to much about Linux, what different things can be the cause of my problem?
Thanks in advance

possibly the router was reset and is no longer passing the ssh connection to the correct server ?

are you able to ssh localhost ?

First check your IP (ifconfig) and make sure that you can ping it . then try to ssh again if you get positive respond.

I would recommend making sure your battery backups are working so that future black outs do not cause this issue.

1. Verify that ipaddress of your box using ifconfig
2. Make sure the sshd is running by typing If you get a /usr/sbin/sshd response, it is. If not, start the service 3. If starting the sshd service, verify the service is running by using the ps command from step 2.
4. Check your iptables to make sure there is no weird REJECT policy.
5. If you are accessing the server on a LAN, there should not be any routers interfering. If you are on a WAN, you will need to check the router config.

We use Red Hat/CentOS so adjust the commands to suit your distro.

Thanks a lot.
I'm at work now and I've been able to try what all of you said. [LIST][*]Definitely, SSH is running..[*]The IP is the same as before[*]Selinux is disabled[*]I haven't been able to know about IPTABLES as I'm not root, the administrator is on holydays, can you imagine?[*]There's supposed to be a 50000-euro SAI, but it's clear it didn't work..

Thanks again, I'm going to try to contact to the administrator...it's a desaster..

I believe you can check whether your machine is listening to port 22 or not as user also

Thanks deep27ak.
Yes I did, and it's listening..

what is the error message you get when you try to connect client using ssh or if possible try using putty if you have any windows client machine

Network error: Connection time out

That means its definitely firewall issue

have you checked the firewall in your local client machine and make sure that if you have disabled selinux then you have to restart your machine for the changes to take affect.

I haven't disabled selinux, it was disabled.(getenforce-->Disabled)
No firewall in Windows machine. It seems it's server firewall,right?

Are you able to ping the server IP?

As it happens that if the ONBOOT parameter is set to no in the config file the Ethernet card does not comes up after restart

I'm not able to ping the server IP
I've checked the ONBOOT parameter= YES

use ifconfig and check if your server's ethernet card is up or not

It's up