Switch IP Config

By certskills December 28, 2011 07:00

This next lab begins with a switch that has been configured to allow Telnet + SSH, including password protection – except the fact that neither switch yet has an IP address. This lab asks you to add the IP configuration to the switches. Details below the fold. Check this link for all the Config labs in this blog. Enjoy!

The Network, Initial State, and Rules

This VM piece uses the simple LAN shown in Figure 1. It shows two switches, connected by a link, with a router on the side.

Figure 1 – Lab Topology

This lab begins with the router configured correctly, but the lab ignores the router configuration for the most part. The two switches have all default configuration, except for the configuration shown here as Examples 1 and 2.

Example 1: SW1 Config

Example 2: SW2 Config

And the general rules:

  • The router has been configured already, and is working.
  • The router is connected to other links, not shown; those links are completely unimportant to the lab.
  • The two LAN switches have no configuration; just before this lab, their config was erased, and the switches were reloaded.
  • This lab uses only ICND1/CCENT concepts, so the link between the two switches is not a VLAN trunk, and only the default VLAN (VLAN 1) is in use.

Now that you have the background, the rest of this post spells out your tasks.

Problem: Choose IP Addresses and Configure Both Switches

As usual, and on purpose, the tasks are straightforward. In this case, the requirements list a subnet, and some comments. You do some subnetting math to decide the IP address for the router interface, the two switches, and the mask to configure. Then configure the IP details, so that the switches can communicate off-subnet and with hosts on the local subnet. That’s it! Details in the list:

  1. Use subnet
  2. Use the numerically highest IP addresses: the highest for the router’s F0/0 interface into the LAN, the next highest for SW1, and the next highest for SW2.
  3. Configure SW1 and SW2 to allow hosts to the right of router R1 (not shown) to be able to Telnet to SW1, or Telnet/SSH to SW2.
  4. As a reminder, note that neither switch uses VLAN trunking, and all ports are in the default VLAN (1).
Answer: Switch Admin Config
Answers: Switch IP Config
By certskills December 28, 2011 07:00
Write a comment


  1. Mit June 11, 01:21

    Mr. Wendell,

    This is not quite related to this particular post. But I would be happy if you can throw some light on my query that I have after reading your book.

    Basically, want to distinguish two things.

    What is the difference when I give an ‘ip default-gateway’ command to a Router and when I define a static default route (ip route ….)?

    Could you please clear this for me? I believe this two won’t mean the same thing. Please correct me if I am wrong. Thanks.


    Reply to this comment
  2. Erik April 26, 18:38

    This lab has caught me off guard. I know subnetting is not mentioned until chapter 11 so I am not sure I have the skills to work this problem after only having finished part two. Do these labs run parallel to the book?

    Reply to this comment
    • certskills Author April 28, 08:16

      Hi Erik,
      Sorry about that. Short answer is that I attempt to tag all the 600+ posts to match the current edition of the book. Honestly, getting that 100% correct is a challenge over time, EG, we’re in the third edition since I published this post 9 years ago. I have re-tagged/re-categorized it for each edition, but it’s easy to miss that kind of dependency.
      I’d say take the approach that if the lab requires something you’ve not seen yet, it’s ok to move on to another post, or the next study todo…

      Reply to this comment
View comments

Write a comment

Comment; Identify w/ Social Media or Email


Subscribe to our mailing list and get interesting stuff and updates to your email inbox.

Thank you for subscribing.

Something went wrong.