If you get errors in Packet Tracer when attempting to generate crypto keys for SSH, try changing the default hostname and setting a domain name.

When you attempt to generate crypto keys in Packet Tracer with this command…

Router(config)# crypto key generate rsa

You may get this error:

% Please define a hostname other than Router.

If so, type this:

Router(config)# hostname NewRouterName

Try again using the original command:

NewRouterName(config)# crypto key generate rsa

If you get this error:

% Please define a domain-name first.

Type this:

NewRouterName(config)# ip domain-name example.com

Now, it should work. Type the original command again:

NewRouterName(config)# crypto key generate rsa