Ques-7 : How Traceroute Works ? | Networking Interview Preparation Series

www.bridgewhy.... is the name of our website where you can find all of our courses.
In this video we talked about one of the most important "Traceroute" command for network Engineers. To understand why and what behind traceroute, you need to understand concept of Time to Live, ICMP protocol and some part of UDP. Once again the video length is more than an hour, because true knowledge seeks patience :). In this video we talked about,
1. Why and what behind traceroute
2. How traceroute works and how we can use it in troubleshooting
3. Wireshark capture of traceroute.
4. Concept of Time to Live
5. Details of ICMP protocol
6. Little bit of UDP
The intent of this video series is not to reveal the questions of networking interview but to understand the networking fundamentals and build your network foundation knowledges. Believe me, if you want to build you networking basics, you need to spend some time and that is why most of my video are of 45 minute to an hour.
We offer various courses including following,
1. Transmission Control Protocol from Scratch !! (Demo Video: • TCP Basics and Connect... )
2. Cisco SD-WAN Design Course from Scratch !! (Demo Video: • Session-1 Cisco's SD-W... )
3. Network Interview Preparation Series !! (Demo Video: • Network Interview Ques... )
All of my course are available in both English and Hindi.
All of our courses are available on bridgewhy.com
Below is the list for courses which we offer,
1. SD-WAN
2. SD-Access
3. Network Security
4. OSPF-BGP-MPLS from Scratch to Design
5. Routing Fundamentals
6. Network Interview Preparation Series.
You can connect me using following medium,
1. www.bridgewhy....
2. Phone Number: 86185 35205
3. WhatsApp: [phone]
4. LinkedIn: / vishnu-dutt-586a9813

[@kirannolan]

sir your doing very noble work 🙏

[@bridgewhy]

Thanks you so much Kiran !!!

[@kevins6886]

OMG this is a master piece and crystal clear
great mate ..!!

[@bridgewhy]

Thank you so much Kevin !!!

[@HumHindustani007]

I have used tracert so many times without knowing inners of what is going on…. Now everything makes sense.

[@bridgewhy]

Thank you so much dear !!!

[@rajindersinghbargari9936]

very well Vishnu, even after my long experience, I learnt it well today.

[@bridgewhy]

Thank you so much Rajinder Bhai. It's an absolute delight to know that these videos are adding something to your experience also !!!!

[@HumHindustani007]

Appreciate your efforts!

[@javieranayapacheco7646]

You are amazing! One thing that I maybe miss: In the tracerout example if R3 does not have a route to R4, will R3 send an ICMP destination unreachable to R1? here the TTL expired is not the problem. Thanks again

[@bridgewhy]

Thanks dear !! I would say, traceroute checks for time exceeded or port unreachable message as explained, but you are right, if there is no route on a router, ICMP by default should send destination unreachable!! But in traceroute you won't see it and you need to debug more !!

[@vishnubalakrishnan3242]

great explanation !!

[@bridgewhy]

Thank you so much Vishnu !!!

[@RiskyRiskForRiskers]

Very awesome training. Many thanks for that. I really mean it. I can't find the wireshark files.

[@bindumadhabghosh7618]

Sir, plz make one video on : if some user getting slow speed then what is the issue and how fix it

[@bridgewhy]

Yup.. will create the video soon..

[@mallikarjunswamy4921]

works for me

[@milandinda9966]

Thank you Sir. 🙂

[@bridgewhy]

You are welcome Milan !!!

[@samsam69775]

Hi Vishnu, amazing video series you have created!!
Have you also created a video for DNS concepts? i dint find it easily

[@bridgewhy]

Thanks Man !! You will see the future videos here bridgewhy.com

[@kevins6886]

I usually get * (star) after several hop's
while doing Traceroute, some device trying to hide their IP ?

[@bridgewhy]

Ah, I forgot to mention that in video.. Actually, the star * at the end of traceroute is because on Cisco routers there is upper limit or CAP configured to reply UDP port unreachable message. This is to stop the denial of service attacks. Hence, the second UDP port unreachable message is not generated by the destination and is not received by the source.. Hence * is there. But at other output lines, may be a star is the result of an intermediate device which is configured to not reply your ICMP messages. Such intermediate devices are Firewall, routers etc..

[@1000cisco]

best

[@mehdizahedi9197]

Wonderful

[@soorajrajendran7128]

so traceroute is an application layer protocol ?

[@bridgewhy]

Cisco and Unix implementation of Traceroute uses UDP to comlete it task.. so you can say that it's a transport layer protocol..

[@rashidmsalim248]

give me some topic of security