Ask Your Question

Help determining network topology given a network trace?

asked 2019-02-16 01:35:50 +0000

Jusb gravatar image

updated 2019-02-16 23:18:20 +0000

Guy Harris gravatar image

Hi folks...

Sorry if this seems like a silly question, but i don't have much experience using wireshark and Packet Tracer. I'm in need of a little help with a project I'm trying to figure out.

The goal here is to examine the wireshark capture, identify information (such as host, hops IP addresses etc) and recreate the topology using Packet tracer.

So to the best of my beginners knowledge, i have tried to recreate the network from what I’ve observed in the capture.

This a trace route from PC # 1 ( to PC #2 ( )

what I see is three ICMP TTL messages coming from 172.19.xx | 172.18.xx… and, so that’s 3 hops. Since PC # 2 has a IP address of, I assume there must be one more router which would presumably

So I’ve created the topology the best I can ( See the screenshot), but something isn’t making sense. For one, i need to assign an ip the fa0/1 interface on router 1, but i'm having trouble putting that together.

I’ve also done the following to allow communication between routers.

router ospf 1

network area 0

*See Screenshot*



Am i on the right track here? Any suggestions help would be very much appreciated.


edit retag flag offensive close merge delete

1 Answer

Sort by » oldest newest most voted

answered 2019-02-16 09:40:11 +0000

Jaap gravatar image

Did you notice that the ICMP errors coming from the upstream interface, facing your host #1? After your ICMP request passes that, without expiring the TTL, it goes on to the next network. So the router with interface has an interface as well. That is the network on which the next interface is the target interface.

edit flag offensive delete link more


Thank you veeerrry much !!!! I appreciate your time.
I spent forever trying to figure this out . I'm pretty new to this, but i'm working really hard preparing myself to do a cert.

Jusb gravatar imageJusb ( 2019-02-16 20:37:32 +0000 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

1 follower


Asked: 2019-02-16 01:35:50 +0000

Seen: 1,810 times

Last updated: Feb 16 '19