How to Configure Telnet on Cisco Router in GNS3

Enabling Telnet on Routers or Switches using GNS3 is a very simple process.

In this article, after creating a network topology using VMware Workstation and Graphical Network Simulator programs, we will examine how to connect to the Router with Telnet via Putty.

How to Configure Telnet on Cisco Router in GNS3

How to Configure Telnet on Router

In order to configure Telnet in the real scenario, you must first connect the Router to your computer through the Console.

After making a console connection, you can configure basic settings and enable Telnet to manage your device from a remote location.

After configuring it, you can connect to the Router via LAN or WAN and configure all your configurations.

There is a big difference between GNS3 and Cisco Packet Tracer programs. You can use all Cisco IOS commands in GNS3. Some commands may not be supported in Packet Tracer.

Before proceeding with the configuration steps, install GNS3 on your computer. If you are using Windows, Linux or macOS, you can install it by referring to the following articles.

How to Enable Telnet in Router

After installing the simulator software, install a new virtual machine on VMware, and then follow the steps below to activate Cisco Telnet.

   Step 1

Click on the symbol below to add the Router to the GNS3 workspace.

Adding a Network Device to GNS3

   Step 2

In the window that opens, select a Cisco Router that you added to GNS3 and drag and drop it into the workspace.

Drag and Drop the Cisco Router to the Workspace

   Step 3

Click All Devices to add Cisco Switch and PC.

Viewing All Devices

   Step 4

Drag and drop the Switch to the workspace.

Adding a Cisco Switch

   Step 5

Add Host to include any virtual machine on VMware Workstation in the network topology.

Adding a Computer to the Workspace

   Step 6

To cable network devices, click the cable option as you see in the image below.

If you see the cross (X) symbol, the wiring option is active.

The important point here is to select a VMnet defined in your computer in the Ethernet NIO section of the Host settings.

In this article, VMnet3 is selected in VMware Network Editor.

Cabling Network Devices in GNS3

   Step 7

After wiring the network devices, a Green Icon will appear on the Switch and PC. If you see the Red Icon, you can understand that the Router is not working.

A Router and Computer Connected to a Switch

   Step 8

Open Network and Internet Settings on your physical computer and configure the VMnet3 network adapter according to the network topology you created.

The IP address created for the new VMnet on the host is 192.168.8.1.

Since the routers often use the IP address with .1 when designing the network, changing the IP address here will avoid any complexity.

Configuring VMnet Settings on a Host

   Step 9

Open the Virtual Network Editor program and configure the IP block of VMnet3 to 192.168.8.0/24.

Also, select Host-Only for VMnet3 and save the settings.

Configure VMnet in Virtual Network Editor

   Step 10

Change the VMware virtual machine’s network adapter setting to Custom / VMnet3.

Configuring the Virtual Machine Adapter

   Step 11

After you have completed the preparations for the Telnet connection, start the Router.

Connecting the VM to GNS3

   Step 12

Double-click on the router to open the CLI command prompt. And then execute the commands below to enable Telnet.

R1# conf t
R1(config)# interface fastethernet0/0
R1(config-if)# ip address 192.168.8.1 255.255.255.0
R1(config-if)# no shutdown
R1(config-if)# exit
R1(config)# line vty 0 4
R1(config-line)# login local
R1(config-line)# exit
R1(config)# username cisco privilege 15 password cisco123
R1(config)# exit
R1# wr

 
Enabling Telnet

   Step 13

Run PuTTY on your virtual computer, and select Telnet as shown in the image below.

Using PuTTY

   Step 14

Enter the FastEthernet 0/0 IP address of the router and type 23 in the port number and click the Open button.

Telnet with PuTTY

   Step 15

After successfully connecting to the Cisco Router, enter the username and password you created!

Typing a User Name and Password for a Telnet Session

   Step 16

As you can see in the image below, you can now setup the Router with Telnet.

Connecting a Router with A Telnet

   Step 17

You can check open sessions on the router by applying the show line command at the command prompt.

show line command

How to Enable Telnet ⇒ Video

You can watch the video below to enable Telnet on your Router or Switch and also subscribe to our YouTube channel to support us!

   Final Word


In this article, we have examined how to connect to a Router / Switch with the Telnet protocol using GNS3 and a virtual machine.

If you want to disable Telnet, type transport input ssh in R1(config-line)#. You can use the no login local command to completely delete the Telnet settings.

The transport input ssh command only allows SSH and disables Telnet. Thanks for following us!

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♦ Cisco TFTP Server

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