Secure Shell (SSH) is a protocol used for transmitting data securely between two systems. It is an effective and secure alternative to Telnet. The SSH service by default runs on port 22. We can use the Nmap syntax, as follows, to enumerate the SSH service:
nmap -p 22 -T4- A -v <Target IP address>
The following screenshot shows the output of the SSH enumeration command we executed. It tells us that the target is running OpenSSH 4.7p1:
