Setting Up SSH on a Cisco Devices (Router and Switches,etc)

In this post I'll demonstrate how to configure SSH on a cisco router.

Below are the commands I used to name the router and provide a domain name. These details are required rior to generating the key. I then generate a 2048 bit RSA key (this took abolut 10 minutes, I should have done 1024). Following the key creation I configure SSH to have a 60 minute timeout, to use SSH version 2 and to exit after 3 failed login attempts. Finally I assign SSH and Telnet (for backup) to my VTY ports and create a user called XcessL.

Configuration Of SSH in Router :

Router>enable

Password:

Router#configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)#hostname R1

R1(config)#ip domain-name home.local

R1(config)#crypto key generate rsa general-keys modulus 2048

The name for the keys will be: R1.home.local

% The key modulus size is 2048 bits

% Generating 2048 bit RSA keys, keys will be non-exportable...[OK]

R1(config)#ip ssh time-out 60

R1(config)#ip ssh authentication-retries 3

R1(config)#ip ssh version 2

R1(config)#line vty 0 4

R1(config-line)#transport input ssh telnet

R1(config-line)#exit

R1(config)#aaa new-model

R1(config)#username xcessl password 0 cisco

R1(config)#exit

Configuration Of SSH in Client Machine through Putty (SSH Software)

I use Putty to connect with SSH and I'm presented with a dialogue to accept the certificate as shown below.

I then log in with my xcessl credentials.

And a quick packet capture shows me that I am encrypting my traffic with SSH.

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