I followed a very helpful info from "A Beginner's Guide to Securing Your Server" topic.
After I installed the firewall and changed the ssh port # from 22 to my choice, I kept disconnected from ssh after a few minutes of idle. However, I was able to log back into ssh.
So in order to increase the ssh session time out, I modified /etc/ssh/sshd_config (with AllowTcpForwarding YES, ClientAliveInterval 120 and ServerAliveInterval 300) as advised elsewhere in the forum.
After a minute, I went ahead and rebooted my server via ssh becasue I found the server load became quite high in WHM.
After the server rebooted, I was able to log back into the WHM and restarted the services, but unfortunately I am NOT able to log into back to ssh anymore. I keep getting “PuTTY Fatal Error, Network error: Connection timed out” error in a little pop up window.
My server is in data center. I use Linksys router at home but it was never been an issue with using ssh or anything such as VPN to other server and so on.
I believe this issue caused by my miss modification to sshd_config file. Or, may be something else. I don’t know how to remove all keepalive setting that I put as I mentioned above.
Did you ever have that similar issue? How did you resolve it?
Please advise me.