SSH vs Telnet - Configure both

Knowledge

SSH and Telnet are both protocols for remote access, but there are differences between the two:

Security: SSH provides encrypted communication, while Telnet is insecure and sends data in clear text.

Port numbers: SSH uses port 22, Telnet uses port 23.

Functionality: SSH provides secure terminal emulation and also supports file transfers, while Telnet only provides terminal emulation.

Authentication: SSH uses public key and password-based authentication, Telnet only uses password-based authentication.

In general, SSH is preferred over Telnet for remote access due to its security and additional functionality.

Skill

SSH

Setting the environment

Make a small network environment similar to the below

Configure the interfaces

Below shows the router configuration for interface gigabitEthernet 0/0/0 with an ip address of 172.16.0.1 and the default subnet mask of 255.255.0.0

Configure the ssh encryption keys

Below are the commands to generate encryption keys. The domain name given is FOC, the router name is changed to FOC1 and the bits assigned is 1024. (the greater the number the higher level of encryption but speed is impacted

Configure the password for ssh login

Here the password is set to friends. Line vty simply means that 16 simultaneous connections can be made. 

Testing

On the command prompt of the pc. Type the ssh -l ..... (then the username and the ip address)

You should now have access via ssh (make sure to type an IP address into your PCs configuration that is on the same network ie 172.16.0.2)

Telnet

Similar to the previous example build a small simulation environment like the below.

Secure the Switch

Set the password for the executive mode, this will be used after the remote login password

Configure the VLAN

Configure interface vlan 1 and give it an IP address

Configure remote login with telnet

Configure the number of simultaneous connections and set the remote login password

Testing

Don't forget to give your PC/laptop an IP address within the same subnet. Telnet + the IP address of the switch. Here I will use the remote login password "friend" and after enable the switch config password "friends"

Higher thinking

There are two methods of remote access here, one with a higher level of security than the other. Do they both have a use within organisations, can you think of when and why these may be.