Explanation
There are four steps required to enable SSH support on a Cisco IOS router:
+ Configure the hostname command.
+ Configure the DNS domain.
+ Generate the SSH key to be used.
+ Enable SSH transport support for the virtual type terminal (vtys).
!--- Step 1: Configure the hostname if you have not previously done so.
hostname carter
!--- The aaa new-model command causes the local username and password on the router !--- to be used in the
absence of other AAA statements.
aaa new-model
username cisco password 0 cisco
!--- Step 2: Configure the DNS domain of the router.
ip domain-name rtp.cisco.com
!--- Step 3: Generate an SSH key to be used with SSH.
crypto key generate rsa
ip ssh time-out 60
ip ssh authentication-retries 2
!--- Step 4: By default the vtys' transport is Telnet. In this case, !--- Telnet is disabled and only SSH is
supported.
line vty 0 4
transport input SSH
Source:
http://www.cisco.com/c/en/us/support/docs/security-vpn/secure-shell-ssh/4145-
ssh.html#settingupaniosrouterasssh