The Secure Shell It is a protocol not a product Software based approach to network security Encrypts the data sent between the computers Client/Server architecture Comes with all Linux distribution, Mac OS X, AIX, Sun Solaris, OpenBSD and other Unix variants Ported to other operating systems, such as Windows, Palm OS, Amiga, etc. Other clients, such as, scp, sftp, etc. are also available Replacement for telnet, rlogin, rsh, rcp, ftp, etc.