Menu Close
Settings Close

Language and Page Formatting Options

20.2. SSH Protocol Versions

The SSH protocol allows any client and server programs built to the protocol's specifications to communicate securely and to be used interchangeably.
Two varieties of SSH (version 1 and version 2) currently exist. SSH version 1 makes use of several patented encryption algorithms (however, some of these patents have expired) and is vulnerable to a well known security exploit that allows an attacker to insert data into the communication stream. 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.

Important

It is recommended that only SSH version 2-compatible servers and clients are used whenever possible.