SSH is a powerful security protocol, but it can prove dangerous if used incorrectly. The paradox of the Internet is that it could never have developed without being open. But that same openness makes today's 'Net vulnerable to attacks of all kinds. The Secure Shell (SSH) protocol is one of a number of solutions developed over the past decade to address this problem.. . .
SSH is a powerful security protocol, but it can prove dangerous if used incorrectly. The paradox of the Internet is that it could never have developed without being open. But that same openness makes today's 'Net vulnerable to attacks of all kinds. The Secure Shell (SSH) protocol is one of a number of solutions developed over the past decade to address this problem.

SSH, for the uninitiated, is a program that's used to log into another computer over a network, run programs on a remote system and move files between computers. Providing strong authentication and secure transmission over open channels (like the Internet), Secure Shell replaces less-secure terminal programs, such as telnet and rsh.

The only way a Unix sysadmin could not know about SSH is if he's been hibernating for the past six years or so. The first thing many admins do upon completing a Unix, Linux or BSD installation is replace telnet and r-utilities (rsh, rcp, etc.) with SSH.