Secure Shell (SSH) is a mechanism for allowing secure remote access to management functions on
a device. SSH provides a function similar to Telnet. Users can log into and configure the device
using a publicly or commercially available SSH client program, just as they can with Telnet.
However, unlike Telnet, which provides no security, SSH provides a secure, encrypted connection to
the device.

The SSH2 implementation is compatible with all versions of the SSH2 protocol (2.1, 2.2, and so
on). At the beginning of an SSH session, the device negotiates the version of SSH2 to be used. The
highest version of SSH2 supported by both the device and the client is the version that is used for
the session. Once the SSH2 version is negotiated, the encryption algorithm with the highest
security ranking is selected to be used for the session.

Device also support Secure Copy (SCP) for securely transferring files between a device and
SCP-enabled remote hosts.

NOTE

The SSH feature includes software that is copyright Allegro Software Development Corporation.

SSH2 is supported in the Layer 2 and Layer 3 codes, and SSH version 1 (SSH1) is no longer
supported. Refer to

Chapter 30, “Configuring SSH1 and SCP”

SSH2 is a substantial revision of Secure Shell, comprising the following hybrid protocols and
definitions:

•

SSH Transport Layer Protocol

•

SSH Authentication Protocol

•

SSH Connection Protocol

•

SECSH Public Key File Format