How to detect SSH version and also What is SSH ?
If you cannot access /etc/ssh/sshd_config because OpenSSH server is running on a remote server, you can test its SSH protocol support by using SSH client program called ssh. More specifically, we force ssh to use a specific SSH protocol, and see how the remote SSH server responds.
The following command will force ssh command to use SSH1:
$ ssh -1 user@remote_server
The following command will force ssh command to use SSH2:
$ ssh -2 user@remote_server
If the remote SSH server supports SSH2 only, the first command with -1 option will fails with an error message like this:
Protocol major versions differ: 1 vs. 2
If the SSH server supports both SSH1 and SSH2, both commands should work successfully.