Telnet – Protocol developed in 1969, allow us to connect to the remote device using the command line interface, telnet protocol is part of the TCP/IP suite. 

To use the telnet, the device should have a telnet client installed and the remote device should be configured to accept telnet connection so most of the devices like servers, routers, switches, firewalls, etc are configured to allow telnet connection.

We can use any telnet client to establish the connection; one of the famous free telnet clients is putty. Putty is used by many organizations as it is open source and it also works for the SSH connection. 

In this packet tracer lab, we will set up a router for telnet access. And then use the command prompt on the computer to test our telnet connection.

To telnet the router from our PC we will have to assign an IP address to our PC. After that, we will assign the IP address to the router interface which is connected with that PC.

For establishing a successful telnet connection, our PC and router should be on the same network as the PC and router are connected directly.

After assigning the IP addresses to both our devices, we have to enable the router for a telnet connection by configuring the VTY lines.

We will configure telnet lines 0-15 on the router, which will allow 16 simultaneous telnet connections to the router, this feature is helpful if more than one person wants to log in to the device at the same time, this type of practice is common if we have many administrators to look after the device.

Once we have configured both devices properly, we can try pinging the router from our PC to check the connectivity. If the router is responding to the ping command then we can establish a telnet connection from our PC’s command prompt.

Once the telnet connection is initiated successfully, we will be prompted with the password to access the router via a telnet connection.

An important thing, we have to configure the privileged mode password. That’s because it is not possible to access the privileged mode through a telnet connection if the password for our privileged mode is not configured. if we will try to access privileged mode without the configuration of the password then we will see an error message saying ‘no password set’.

 

 

Telnet in cisco devices

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Lab tasks

  1. Set pc0 IP address to 192.168.1.2/24
  2. Set interface fast Ethernet 0/0 IP address to 192.168.1.1/24
  3. Set privileged mode password to Cisco
  4. Enable telnet lines on router
  5. Test telnet connection via your PC