Q: How do I enable SSH logins on my routers?

A:

First, make sure you're using a version of IOS that supports SSH. I'm using 12.4. Turn on new-model logins (make the password better than my example):

aaa new-model
username cisco password cisco

Give it a FQDN, which is needed for key generation, and then generate a key. The key name will be devicename.domain-name:

ip domain-name example.com
cry key gen rsa

Check the key with show cry key mypub rsa. Now make the vty logins use ssh:

line vty 0 15
 transport input ssh

And define some ssh settings:

ip ssh ver 2
ip ssh source-int f0/0