Linux – Can’t SSH into Linux server

Here is a series of steps you can use to diagnose the problem:

1. Check if sshd is running on the host(ps -ef|grep ssh)
2. Ensure that sshd is binding to port 22 using netstat (netstat -al|grep "LISTEN " should work)
3. See if you can connect to the real IP address via ssh from the host machine (if not, there is either a local firewall, or sshd is not working as it should
4. Try to ping the host from the client machine (if this fails, there is a routing problem)
5. Try to telnet to port 22 from the client machine (telnet 192.168.1.1 22) (if this fails, a firewall is blocking you)
6. Finally, if all the above succeed, but you cannot ssh using the ssh client - re-install your ssh client.

"Connection Refused" is very specific. It means that when you tried to connect to this service (by sending an SYN packet), you got a specific response (a RST packet) meaning "the server is there, but not offering a service on that port. without any firewalls in the way, this is the response you'd get if nothing was actually listening on that port. Since you've verified that something IS listening on that port, this response MUST have come from some firewall, Either the firewall on the server itself (which you could check with iptables -L -n) or some other firewall in between you and the server. If its not the server itself, it could be any other router in between server and client.

This all assumes that you try to telnet to the correct ip address.