17.2. SSH Protocol Versions
The SSH protocol allows any client and server programs built to
the protocol's specifications to communicate securely and to be
Two varieties of SSH (version 1 and version 2) currently
exist. The OpenSSH suite under Red Hat Enterprise Linux uses SSH
version 2 which has an enhanced key exchange algorithm not
vulnerable to the exploit in version 1. However, the OpenSSH suite
does support version 1 connections.
It is recommended that only SSH version 2-compatible servers and
clients are used whenever possible.