Problem:

How to enable SSH in Cisco IOS



Solution:


Please follow these steps to enable SSH on a Cisco 7200 router.

Router(config)#hostname myrouter
myrouter(config)#ip domain-name gho.no
myrouter(config)#crypto key generate rsa general-keys
The name for the keys will be: myrouter.gho.no
Choose the size of the key modulus in the range of 360 to 2048 for your
General Purpose Keys. Choosing a key modulus greater than 512 may take
a few minutes.

How many bits in the modulus [512]: 1024
% Generating 1024 bit RSA keys, keys will be non-exportable…[OK]
*Sep  6 16:00:27.417: %SSH-5-ENABLED: SSH 1.99 has been enabled

SSH version 1 is prone to a lot of vulnerabilities, you should use SSH version 2.

Router(config)#ip ssh version 2

To verify that you are indeed running SSH version 2, you can issue the show ip ssh command in exec mode.

myrouter#sh ip ssh
SSH Enabled – version 2.0
Authentication timeout: 120 secs; Authentication retries: 3