Cisco Systems 3750E Understanding SSH, SSH Servers, Integrated Clients, and Supported Versions

Chapter 9 Configuring Switch-Based Authentication

Configuring the Switch for Secure Shell

For SSH configuration examples, see the “SSH Configuration Examples” section in the “Configuring Secure Shell” section in the “Other Security Features” chapter of the Cisco IOS Security Configuration Guide, Cisco IOS Release 12.2, at this URL:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuration_guide_chapter0918 6a00800ca7d5.html

Note For complete syntax and usage information for the commands used in this section, see the command reference for this release and the “Secure Shell Commands” section of the “Other Security Features” chapter of the Cisco IOS Security Command Reference, Release 12.2 at this URL:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_command_reference_chapter0918 6a00800ca7d0.html

Understanding SSH

SSH is a protocol that provides a secure, remote connection to a device. SSH provides more security for remote connections than Telnet does by providing strong encryption when a device is authenticated. This software release supports SSH Version 1 (SSHv1) and SSH Version 2 (SSHv2).

This section consists of these topics:

•SSH Servers, Integrated Clients, and Supported Versions, page 9-38

•Limitations, page 9-39

Note The SSH connection to the Catalyst 3750-E-only stack can be lost if a stack master running the cryptographic software image and the IP base or the IP services feature set fails and is replaced by a switch that is running a noncryptographic image and the same feature set. We recommend that a switch running the cryptographic software image and the IP base or IP services feature set be the stack master. Encryption features are unavailable if the stack master is running the noncryptographic software image and the feature set.

SSH Servers, Integrated Clients, and Supported Versions

The SSH feature has an SSH server and an SSH integrated client, which are applications that run on the switch. You can use an SSH client to connect to a switch running the SSH server. The SSH server works with the SSH client supported in this release and with non-Cisco SSH clients. The SSH client also works with the SSH server supported in this release and with non-Cisco SSH servers.

The switch supports an SSHv1 or an SSHv2 server.

The switch supports an SSHv1 client.

SSH supports the Data Encryption Standard (DES) encryption algorithm, the Triple DES (3DES) encryption algorithm, and password-based user authentication.

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

9-38 OL-9775-02