SSH:TDG
SSH: The Secure Shell (The Definitive Guide)
Barrett, Silverman, & Byrnes / O’Reilly

Tools


sshquery

sshquery is a Perl script which briefly connects to an SSH server, then prints out some useful information about it:

Works with either SSH-1 or SSH-2. Run sshquery --help to get usage information. Requires the Math::BigInteger package, available from CPAN.