Jesin's Blog

Welcome to the Portal of Technology

  • Facebook
  • GitHub
  • Google+
  • RSS
  • Twitter
  • Home
  • Categories
    • Domains
    • Linux
    • Networking
    • PHP
    • Virtualization
    • Web Design
    • Web Servers
    • Windows
  • WordPress Plugins
    • Custom Error Pages
    • HTTP Digest Authentication
    • Mailgun Email Validator
  • Toolbox
    • DNS Lookup Tool
    • htdigest Generator Tool Online
    • htpasswd Generator Tool Online
    • HTTP Headers Lookup Tool
    • MD5 Encryption Tool
    • Open Port Check Tool
    • SHA-1 Encryption Tool
    • URL Encoding/Decoding Tool
  • About Me
  • Contact Me
  • Sitemap
Home ›
Networking ›
Configure Cisco Routers and Switches for Telnet Access

Configure Cisco Routers and Switches for Telnet Access

July 21, 2011 Networking Jesin A 7 Comments

networking category thumbnail

I wanted to start from the basics as this is the first article under the category Networking. A Tutorial on How to Configure Cisco Routers and Switches for Telnet Access. Lets start with some info about the Telnet protocol – Telnet uses port 23, this protocol is used for remote administration of devices through commands. Take note that Telnet sends commands as plaintext over the network so don’t use telnet this unless you’re on a testing environment or 101% sure your network is safe from intruders.

Configuring Cisco Routers for Telnet access

Assuming you’ve configured the interface IP address settings properly just entering the following commands will configure your cisco router for telnet access.

Router>enable
Router#configure terminal
Router(config)#enable secret password
Router(config)#service password-encryption
Router(config)#line vty 0 4
Router(config-line)#password telnetpw
Router(config-line)#login

The command enable secret sets a privilege mode password and stores it in an encrypted format so that it isn’t visible when viewing the running configuration. If you already have a privilege mode password set ignore the command. Replace the word password with your strong password. Similarly after the “line vty” command replace telnetpw with your telnet password. The “service password-encryption” stores the telnet password in encrypted format.

Configuring Cisco Switches for Telnet access

To Configure Switches for telnet access we use the same commands as seen above with one addition. Switches being Layer 2 devices do not have any IP addresses assigned by default, so we’ll assign an IP address to a VLAN interface which I’ll show you how. Follow the commands below

Switch>enable
Switch#configure terminal
Switch(config)#enable secret password
Switch(config)#service password-encryption
Switch(config)#line vty 0 4
Switch(config-line)#password telnetpw
Switch(config-line)#login
Switch(config-line)#exit
Switch(config)#int vlan 1
Switch(config-if)#ip add 10.0.0.1 255.0.0.0
Switch(config-if)#no shutdown

Replace the word password in the “enable secret” command to your preferred privilege mode password, also replace telnetpw with your telnet password. When you configure the VLAN interface enter the VLAN number in which the TELNET CLIENT (this is the system FROM which you will execute the telnet command) is located. If you haven’t configured VLAN just enter 1, as for the IP address it should be in the same subnet as the Telnet client and the IP address should be unique i.e., it should NOT be assigned to any other host on the network.

Go to your system and telnet to the router/switch

PC>telnet 10.0.0.1
Trying 10.0.0.1 ...Open
User Access Verification
Password:
Switch>

Important:- As said earlier Telnet sends commands and passwords in plaintext over the network. The “enable secret” and “service password-encryption” commands only STORE the password in encrypted format

Related posts:

networking category thumbnailConfigure Cisco Routers for SSH Access networking category thumbnailConfigure Cisco Console Password networking category thumbnailConfigure Inter-VLAN routing on Cisco Router networking category thumbnailHow to Configure PPP in Cisco Routers networking category thumbnailHow to recover a Cisco device password

Tags: cisco

Comments

  1. Adnan says

    March 16, 2015 at 7:03 pm

    Thanks, helpful and useful.

    Reply
  2. Bhanu Prakash SG says

    March 30, 2016 at 12:03 pm

    Super Post learned a lot

    Reply
  3. nizam says

    May 2, 2016 at 11:19 am

    simple explanation..Appreciate!

    Reply
  4. Adim belema says

    September 3, 2016 at 8:17 pm

    Learned allot, networking is a best course

    Reply
  5. Sebastian says

    November 16, 2018 at 5:51 pm

    What do I do when my switch doesn’t have a specificly marked console port? I have the SLM2048 and there are only 48 gbe ports and two fiber ports on the front panel. Nothing else. The switch denies connections on both port 22 and port 23.

    Reply
    • Jesin A says

      November 16, 2018 at 5:58 pm

      That switch has a web interface. Instructions are provided on page 7 of this document.

      Reply
  6. FERNANDEZ says

    May 22, 2019 at 5:00 pm

    Good document
    Just one point
    If an VLAN 5 for example il leading 3 access ports on that VLAN
    WhatI have to do for limiting the Telnet to only one of those 3 ports
    regards
    Enrique

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Get a wealth of information delivered to your inbox. Subscribe and never miss a single article.

  • Tutorials and howtos
  • Code, scripts and commands
  • Online Tools

* No spam, unsubscribe anytime

Hire Me

  • SSL installation and hardening (A+ on Qualys SSL test)
  • Apache & Nginx configuration
  • Email deliverability improvement (10/10 on Mail Tester & MailGenius)
  • WordPress customization, optimization and migration
  • and much more…

    Tools

    • DNS Lookup Tool
    • htdigest Generator Tool Online
    • htpasswd Generator Tool Online
    • HTTP Headers Lookup Tool
    • MD5 Encryption Tool
    • Open Port Check Tool
    • SHA-1 Encryption Tool
    • URL Encoding/Decoding Tool

    Nav

    • Home
    • About Me
    • Contact Me
    • Privacy Policy
    • Sitemap
    Vultr SSD VPS

    Creative Commons License
    Jesin's Blog by Jesin A is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
    Based on a work at websistent.com.