FREE CCNA Lab 016: Loopback Interface Configuration

[@JeremysITLab]

I hope you're enjoying the labs! If you want another great set of FREE packet tracer labs for the CCNA, check out Neil Anderson's lab guide here: jeremysitlab.com/ccna-lab-guide

[@BijouBakson]

Gave me a chance to do a little practice on routing table. Good practice. Simple exercice, beat 30 min lesson - but of course first you gotta take the lesson. Jeremy, you are appreciated.

[@ZTsarmadOne]

Thanks 😊.

[@mrgraphic7175]

Hey Jeremy! First of all, thank you for your amazing stuff! One question: I know that Loopback IPv4 Address usually is 127.0.0.1 (by default), but can be set between 127.0.0.0 - 127.255.255.255. I guess you just use it for explanation purposes only and in a real situation would be between 127.0.0.0 - 127.255.255.255. Thank you, man! All the best!!!

[@JeremysITLab]

This video is about loopback interfaces, not loopback addresses. They are two different concepts!

[@mrgraphic7175]

@@JeremysITLab Understood! Thanks a lot!!!

[@essuthetaekwondoin]

thank you Jeremy IT Lab

[@DevOpsPulse]

thank you

[@beworld_pasha]

nice one, i appreciate it

[@pixelatedlava]

Thank you sooooo much!!!

[@SANTOSHSHRESTHA111]

Now if we remove the physical connection. Can we ping between routers ???

[@JeremysITLab]

How will the electrical signals from one router reach the other one?

[@SANTOSHSHRESTHA111]

@@JeremysITLab physical connections between routers. Isnt that the reason we use loopback ip ? So if the main connection breaks down, signal transfers from logical connection that is loopback ? Can u please help me to get out of confusion

[@JeremysITLab]

@@SANTOSHSHRESTHA111 But there is only one physical connection between the routers. If it goes down, there’s no way for a signal to travel between them.

[@SANTOSHSHRESTHA111]

@@JeremysITLab then what is the use of Loopback ip ?

[@JeremysITLab]

@@SANTOSHSHRESTHA111 It provides an interface that isn't dependent on the status of a single physical interface

[@markbenyosef3504]

Hi jeremy i've created and completed all steps in the lab16 , but ping loopback is not working. what protocol do you use in lab16 ? Thanks.

[@ashutoshverma3216]

mine also

[@Babqa]

​@@ashutoshverma3216 you need to do static route from R1 to R2. use command ip route 2.2.2.2 255.255.255.255 192.168.1.1 on first router and it should be works. Just to the same on R2. I did a same problem :)

[@vivekhananth2724]

Hi for me both loopback ips not pinging in both routers.

[@mustafasaifuddin5492]

How to do static routing of 2 routers only? As static routing uses ip of router not connected directly

[@JeremysITLab]

You configure the routes exactly like any other static route, there's no difference.

[@manuelstausberg8923]

I was somewhat confused why I was able to ping the respective loopback interfaces without configuring a route :D

[@JeremysITLab]

I decided just to pre-configure the routes since I hadn't covered routes at this point in the labs, but I suppose I could have just included them in this lab! It's a pretty simple command after all.

[@johnmanuelalvaradomendoza6356]

How could the Lo0 be represented in packet tracer. In my SRWE skills assessment (which I already passed yesterday) the router has a loopback Lo0. Yet I wonder how it was done to represent the Lo0 loopback in the activity. In my intent to reproduce the skills assessment, I can setup all the equipment (2 PC´s, 2 switches, and router) along with their connections. Yet to show the router with the symbology representing the Lo0, I cannot figure what to use. For in the original activity it has ---|Lo0 drawn to represent the loopback.

[@carlosadan9836]

You didn't explain that you created a static route for r1 to know r2's loopback ip address and for r2 to know r1's loopback ip. If you do not create the route you cannot ping.

[@JeremysITLab]

Carlos Lobo As I said in response to another comment, I hadn’t covered static routes yet so I left it out. Looking back, if I remade this I’d briefly explain it and show the command I suppose.

[@carlosadan9836]

@@JeremysITLab Thanks

[@clarklk]

I am confused why the physical interface addresses you used are private (192.168.X.X) but the loopback addresses you used are not in any of the ranges of IPv4 private addresses. I would think you would want to use private addresses.

[@JeremysITLab]

Loopbacks are often used to simulate remote networks in labs, so using public IP addresses is common.

[@clarkkinser8523]

If you are using public addresses for the loopback interfaces wouldn't you have to register them with a public IP address registration authority? And aren't most, if not all, IPv4 public addresses already used?

[@purplecrayon7281]

@@clarkkinser8523 it is assumed that the company was given the network 1.0.0.0/8 and 2.0.0.0/8 by the ISP.