Extreme 3804 User Guide

Summit24e3 Switch Installation and User Guide

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To re-enable Telnet on the switch, at the console port use the following:

enable telnet

You must be logged in as an administrator to enable or disable Telnet.

Using Secure Shell 2 (SSH2) 

Secure Shell 2 (SSH2) is a feature of ExtremeWare that allows you to encrypt Telnet session data 
between the switch and a network administrator using SSH2 client software. The ExtremeWare SSH2 
switch application is based on the Data Fellows

™

 SSH2 server implementation. It is highly 

recommended that you use the F-Secure



 SSH client products from Data Fellows corporation. These 

applications are available for most operating systems. For more information, refer to the Data Fellows 
website at:

http://www.datafellows.com. 

Because SSH2 is currently under U.S. export restrictions, before enabling SSH2, you must first obtain a 
security license from Extreme Networks. The procedure for obtaining a security license key is described 
in Chapter 3, “ExtremeWare Overview”. 

To enable SSH2, use the following command:

enable ssh2 {port <tcp_port_number>}

An authentication key must be generated for each SSH2 session. This can be done automatically by the 
switch or by the client application. To have the key generated by the switch, use the following 
command: 

config ssh2 key {pregenerated}

If you do not select automatic key generation, you are prompted to enter the key when you enable 
SSH2. 

You can specify a TCP port number to be used for SSH2 communication. By default the TCP port 
number is 22.

The supported cipher is 3DES-CBC. The supported key exchange is DSA. 

For additional information on the SSH protocol refer to [FIPS-186] Federal Information Processing 
Standards Publication (FIPSPUB) 186, Digital Signature Standard, 18 May 1994. This can be download 
from: ftp://ftp.cs.hut.fi/pub/ssh. General technical information is also available from 
http://www.ssh.fi.