Scenario:

You want to enable ssh access to manage a cisco device, but don’t want to use AAA.

Solution:

First, make sure a local username/password is defined on the device

Router(config)# username admin password cisco

Second, Generate a general use key for the ssh encryption:

Router(config)# crypto key generate rsa general-keys exportable

This message will appear next, enter one of the three common values at the prompt: 512, 1024, 2048

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]:
% Generating 512 bit RSA keys ...[OK]

Next, change ssh to use version 2:

Router(config)# ip ssh version 2

Configure the vty lines, which is used when accessing the device:

Router(config)# line vty 0 4

Important next step: Tell the router to authenticate using local authentication – otherwise login will fail

Router(config)# login local

Configure lines to only accept ssh logins, which effictively disables accessing the device via Telnet :

Router(config)# transport input ssh