Enabling SSH on a Cisco router is not enough to guarantee SSH is working.
Enabling ssh version 2.0 on a routers is as straight forward as;.
>ip ssh version 1-2
I surely recommend the use of version 2, because ssh v1 has a bug which allows root access.
Anyhow… ssh needs some sort of encryption to work. In other words create a crypto key.
host(config)#crypto key generate rsa modulus 2048 The name for the keys will be: host.somenetwork.com % The key modulus size is 2048 bits % Generating 2048 bit RSA keys, keys will be non-exportable... [OK] (elapsed time was 2 seconds) host(config)# Nov 5 14:17:17.240 UTC: %SSH-5-ENABLED: SSH 2.0 has been enabled
The good thing is the crypto key is not saved in config. The bad thing is, whenever you commission a router and forget to create the crypto key it can cost you some time in troubleshooting. Worst case you have to travel on-site to create the crypro key.
By the way, make sure you enable ssh on the VTY ports and if applicable deny telnet input.
line vty 0 15 transport input ssh no transport input telnet
And create an access-list and apply it to the VTY ports.
FYI: SSH enables encrypted CLI access towards a host. And the crypto key validates the host communication i.e. detection of a man-in-the-middle attack.