How TCP really works // Three-way handshake // TCP/IP Deep Dive

You need to learn TCP/IP. It's so much part of our life. Doesn't matter if you are studying for cybersecurity, or networking or something else. Learn TCP/IP.
// MENU //
00:00 ▶️ Intro
01:32 ▶️ The beginnings of TCP
03:57 ▶️ Three way handshake
07:20 ▶️ SYN meaning/explanation
08:50 ▶️ Port numbers
09:58 ▶️ What actually happens in the handshake
14:19 ▶️ Common starting TTL values
15:04 ▶️ Why we need SYN numbers
16:11 ▶️ What actually happens in the handshake (cont'd)
19:00 ▶️ Q&A (SYN,SYN-ACK,ACK - Sequence numbers - Increments - Tips)
33:01 ▶️ History of TCP
34:44 ▶️ TCP options
36:56 ▶️ TCP flags
41:53 ▶️ TCP Window - window size and scale
59:04 ▶️ MSS (Maximum Segment Size)
59:49 ▶️ SACK (Selective Acknowledgement)
01:00:13 ▶️ Conclusion
// PCAP File //
Wireshark TCP pcap file: www.dropbox.com/s/l5p8ofik86z...
// MY STUFF //
www.amazon.com/shop/davidbombal
// SOCIAL //
Discord: / discord
Twitter: / davidbombal
Instagram: / davidbombal
LinkedIn: / davidbombal
Facebook: / davidbombal.co
TikTok: / davidbombal
KZbin: / davidbombal
//CHRIS GREER //
LinkedIn: / cgreer
KZbin: / chrisgreer
Twitter: / packetpioneer
Pluralsight: TCP Analysis Course: davidbombal.wiki/tcpwireshark
// SPONSORS //
Interested in sponsoring my videos? Reach out to my team here: [e-mail]
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Please note that links listed may be affiliate links and provide me with a small percentage/kickback should you use them to purchase any of the items listed or recommended. Thank you for supporting me and this channel!
#wireshark #tcp #hacking

[@haphamdev]

I'm a software developer with a little networking background. Today I've learnt a lot more networking knowledge than my 5 years at the university. What a brilliant video. Thank you very much.

[@saucegotti8538]

sounds like you didn’t pay attention in university

[@HungNguyen-zx5zf]

@@saucegotti8538 not everyone could handle all knowledge (and remember them) from university until they get their hand dirty on real world, genius.

[@anonShrivastav]

​@@saucegotti8538😂

[@mwafulirwa1]

@@saucegotti8538 it depends on the university i thnk...my college sucked, had to learn almost 90% of the things i know now on my own

[@dbug7276]

😅😅😅😅😂😂😂😂🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣 Madman

[@Jarek.]

I couldn't believe that I would watch 1hr video on 3-way handshake and claim it was fascinating!

[@davidbombal]

Glad you enjoyed it! 😀

[@JeremysITLab]

Found my weekend watching! Great stuff, loving the details on TCP.

[@davidbombal]

Thanks Jeremy! Great to see you here again 😀

[@junaidjaved4792]

Jeremys IT lab sir 😍😍😍😍😍❤❤❤❤

[@nevarius9010]

The GOAT

[@aaqibshafiq5468]

Please add some topics :-dhcp/dns/arp

[@evanstayuka381]

Jeremy IT Lab, Sir your lessons are gold

[@thecuriousengineer]

This is the greatest TCP/IP lesson I have ever watched. Thank you both, David and Chris! :)

[@ZeyRonTT]

I thought CCNA 200-301 had a lot of information about TCP ... Until I watched this video, thanks for a great video. Learned alot

[@CFH298]

Can you create a playlist containing all videos with Chris? This was so invaluable and combined with reading TCP/IP Guide it all makes sense. Thanks all!

[@davidbombal]

Here you go: kzbin.info/aero/PLhfrWIlLOoKO8522T1OAhR5Bb2mD6Qy_l

[@CFH298]

@@davidbombal You’re the best :)

[@SiddhantSwami]

@@davidbombal You are the best, David!!!!!!

[@AshleyEhSMR]

@James Great question! Appreciate you 🎊 And David wasted no time. The playlist I didn’t know I needed today ❤️🙌🫶

[@simplekindofman8867]

This is so incredibly thorough. Great job!!

[@phil2768]

When you can listen to something like this as a podcast (not watching), while working on something else (I was tidying up), and can understand everything that was talked about then you know that the person talking not only knows what they are talking about, inside and out, but can also explain and teach it clearly. That was excellent 👌🏻

[@CyberNancy]

I appreciate how David and Chris present the basics, while so much of the modern movement has forgotten these core elements.

[@confidential303]

you may say with confident most of people don't know this

[@IMAND93]

It really shows how much Chris is more experienced with teaching. A great way of repeating the same thing in different ways until it makes sense. That's why I like your videos, guys. Overall very informative video, about Wireshark and TCP both.

[@nuxboxen]

I have to say WOW... the way you two work together is just tremendous. This is really easy to listen to and really conducive to learning.

[@MSSMusChaos]

One full hour of knowledge, thank you Chris for giving a easy-to-follow introduction.

[@samhull8028]

Spot on, there is so much info to take in, will need a few repeats, but loved the indepth walkthrough, really helps to understand. Chris's enthusiam is brilliant, you kept the pace managable, like slowing to 10base from Chris's 1000base. lol thanks

[@kapilsonyt]

Been following Chris for long time and having watched his all TCP wireshark videos, it's glad to have you here digged deeper TCP again for us. Thanks David and Chris.

[@davidbombal]

Thank you and you're welcome!

[@ChrisGreer]

Thanks Kapil! Great to meet you.

[@mikkio5371]

i have to come back and watch this . nice Chris . practically explained

[@partspieces8165]

I'm loving these interviews with David & Chris. Really is valuable. 2 networking pros having a talk like a teacher & student scenario for us beginners to understand better & making it more engaging. Thanks so much!

[@webplethora]

Thank you David and Chris for this fanstastic session. These sessions are really empowering and the in-depth knowledge that is imparted through this video is enlightening. I am truly grateful for this. Once again, thank you David and Chris.

[@drumaddict89]

about 5 minutes in and LOVE how he describes and teaches stuff. thanks for your videos david! always a pleasure to expand my horizon with your content

[@klwthe3rd]

Unlike the John Hammond video, this content is extremely valuable. Chris is an expert in the networking/packet analysis field and did a beautiful job breaking down these concept so one learning Wireshark gets the most out of the data packets and software. You need to create a play list just with Chris, having all his topics under one place. This just might be the single best educational video on the 3 way handshake on KZbin. I would like to see common problems/solutions that occur often in the real world where Chris would be called out for diagnosis.

[@bsparky01]

I know this is a two month old video, but I just wanted to thank you and Chris for putting this information out there. I have learned a lot from watching Chris' Wireshark videos, but this has been very educational as to why I am seeing what I see in the captures. I am not a network engineer/admin, but I end up spending a lot of time at work having to analyze network traffic because the application I support for my company is very latency sensitive and videos like these help me speak a common language with network folks to help get to the root of a complications. Thanks again for this and I am eager to dive into more!

[@shannon1573]

Thank you! Thank you! Thank you, David and Chris! I'm currently taking a college TCP/IP course & I think I've learned more in the last hour than I have in the last month! Our textbook is the TCP/IP Illustrated (2012) & although I I'm blown away by the technical details, I barely understand any of it. I also spend an ungodly amount of time researching what's still relevant. I've used Wireshark many times, but this video helped me UNDERSTAND it. TCP/IP is a prerequisite for my future Firewalls/Network security, OS Security & Routers classes, so I'm grateful for these videos to help me learn such a daunting subject. Please keep this series going!

[@wiltonwell]

Thank you Chris and David you took me on learning trip with, there all the way. I have learnt from the best and you deserve more than I can give you both. I will continue watching your content, for me achieve my goal. It is people like you that are unsung heros of people for me that is trying my best to get there.

[@teomcam]

Wow what an episode. I can’t think of a word to thank you both enough for the treasure you giving us.

[@jean-ericrioux4726]

This is so well explained. I will use this video as a complement to the training I do internally to colleagues. I'm somewhat THE tcp and Wireshark guy at work, and often gets technical questions / request to troubleshoot something, even protocols I never worked with. Here's some things I really liked in this video: - When you mentionned to ''Please capture the TCP handshake''. You're so spot on ! It's just so critical to have - In TCP Options, MSS is not negociated but announced. (so many times I had to tell people this) - SACK has to be enabled and announced in both Syn and Syn Ack. Here are some suggestions of topic you could discuss in the future: - Same video with ICMP (explaining all the codes, etc) - A bit more depth on MSS (MSS vs MTU and fragmentation issues....just had one yesterday! :) ) - Get some packet loss captures and demonstrate where is the packet loss (example: If you see original packet + retransmission you can assume the loss is after the capture point, etc, etc) Great work !

[@educastellini]

-Great content professor David Bombal, and Chris Greer...!!! -Always nice when we look at the essentials in depth again. -TCP/IP, Three way handshake is the basis of almost all communication that we have in the network. -Great, this conversation and remembering in depth what we studied with the view of colleagues....!!! -Thanks for the knowledge teachers David Bombal, and Chris Greer...!!!

[@stuartwill1992]

This is fantastic content, hearing the real life context of this system TCP/IP and the deep dive into how it works is great!

[@jonathantx]

Thank you for making kind of knowledge available to everyone. This really makes a difference when your new and starting to put things together in your mind and breaking out doing tasks on your own in a production network.

[@samanthamorris3453]

Thanks for the video! In my professional life, one of the things that has really distinguished my more senior colleagues is their ability to understand TCP/UDP flows during troubleshooting. This video really helped me get an idea of what their brains may be thinking when we troubleshoot together! This is a video I'll watch multiple times.

[@sureshjoshi5933]

You guys are incredible! I've been looking for videos like this for a long time. Attaching the pcap file is a great idea so that person can follow along with your flow!

[@greob]

Another GREAT video! Love this series and love Chris, such a great teacher. Would love to see more about QUIC and UDP as well.

[@JudgeGideon823]

Love this practical knowledge. I am convinced, or rather confident that my career will be significantly more enjoyable and valuable if I understand Networking like you gentlemen. Like anything we don't know, it can be confusing and challenging, but once we pass those hurdles it's incredibly satisfying and worthwhile. Thank you David for what you do and for introducing us to some great people and professionals. Absolutely invaluable stuff here.

[@ricardow1130]

Just started studying for my eJPT and holy smokes did this video add value to what I've just learned. Can't wait for more in depth!

[@ok-jq1jh]

THANK YOU! Finally what I've been seeing in tcp packets makes much more sense thanks to you guys. I do appreciate it, definitely love the deep dives keep it up!

[@davidbombal]

// MENU // 00:00 ▶ Intro 01:32 ▶ The beginnings of TCP 03:57 ▶ Three way handshake 07:20 ▶ SYN meaning/explanation 08:50 ▶ Port numbers 09:58 ▶ What actually happens in the handshake 14:19 ▶ Common starting TTL values 15:04 ▶ Why we need SYN numbers 16:11 ▶ What actually happens in the handshake (cont'd) 19:00 ▶ Q&A (SYN,SYN-ACK,ACK - Sequence numbers - Increments - Tips) 33:01 ▶ History of TCP 34:44 ▶ TCP options 36:56 ▶ TCP flags 41:53 ▶ TCP Window - window size and scale 59:04 ▶ MSS (Maximum Segment Size) 59:49 ▶ SACK (Selective Acknowledgement) 01:00:13 ▶ Conclusion // PCAP File // Wireshark TCP pcap file: www.dropbox.com/s/l5p8ofik86zeieh/TCP-Handshake_ChrisGreer.zip?dl=0 // MY STUFF // www.amazon.com/shop/davidbombal // SOCIAL // Discord: discord.com/invite/usKSyzb Twitter: twitter.com/davidbombal Instagram: instagram.com/davidbombal LinkedIn: www.linkedin.com/in/davidbombal Facebook: facebook.com/davidbombal.co TikTok: tiktok.com/@davidbombal KZbin: kzbin.info //CHRIS GREER // LinkedIn: www.linkedin.com/in/cgreer/ KZbin: kzbin.info Twitter: twitter.com/packetpioneer Pluralsight: TCP Analysis Course: davidbombal.wiki/tcpwireshark // SPONSORS // Interested in sponsoring my videos? Reach out to my team here: [e-mail] Please note that links listed may be affiliate links and provide me with a small percentage/kickback should you use them to purchase any of the items listed or recommended. Thank you for supporting me and this channel!

[@trentmcgrath9712]

EXCELLENT

[@joelhorensma8036]

David, are you really ex NSA or is it a media stunt?

[@TampaRedd]

What software was used to capture this podcast/video? I know it's not Zoom, appears to be full HD or better quality.

[@vicdan90]

@David Bombal Hello, We would like to listen about future of Data Sciencist ,plus their Job roles. Your Thoughts will be great to us who Interest and will invest their learning in this data scientist roles . Thanks since now on.

[@samratchapagain4804]

Loving the way he explains the TCP like the real world examples. Eager to wait for another episode like problem of window scale size and many more. Thanks david and chris :)

[@samahhabib18300]

i watched the video on pluralsight explaining the tcp, and i think this is the most simplified explanation, the questions from David make the difference. and expiations from Chris were great. thank you all.

[@noevaz]

I saw this video a few months ago and I struggle a lot to understand, after reading some material and practicing I watched the video again and I really understand more about TCP, definitely you need to spend time and be PATIENT when learning this topics, great video David and Chris!

[@ged4440]

David and Chris, this is fantastic. I have watched so many presenters to learn this stuff and Chris, you are amazing in the way you teach it!

[@dravidianChief]

1hr well spent. Thank you guys. Definitely need a series. Nailed the basics of TCP/IP. Thank you!

[@Johno3998]

Man, the concept of "splitting the OSI model in half" to troubleshoot is such a good one, I've never thought of that

[@juanrebella2589]

Absolutely amazing masterclass. Thank you Chris and David, superb material. Juan.

[@KhurramSSiddiqui]

I opened this video a couple of days ago and finally came to watch it over the weekend. Great video, awesome presenters!

[@willd9807]

This is the most valuable video i have found on youtube or anywhere regarding packet sending. The only way it could be extended more is how the actual wire (or photo optic) is transferred from point to point. This video is priceless and belongs in Universities as a compulsory IT or Comp Sci must watch

[@tylerroman6065]

Absolutely loved the video! I'm currently doing research on Multi-path TCP so its amazing to have better understanding of TCP! Thank you!

[@ausafahmad8335]

Hey David, This video was just awesome. I am currently studying medicine but I've always been interested in computers. Once I'm done with med school I'm going to start with a computer science course and your videos keep my interest ignited. Thanks a lot !

[@charlesikpeme7777]

Thanks David, the networking world is better because of you. Thanks for mentoring millions of people.

[@davidbombal]

Thank you Charles!

[@madusankasampathweerasingh8570]

I cannot believe that I watched the whole video without skipping! Superb explanation!

[@dhughes19962009]

I took a course that walked me through tcp among other things, but i didnt understand the importance and utility of it till watching this video. I very much appreciate the knowledge. Thank you both for your generosity in sharing with us all.

[@deenarshahid]

It's been amazing experience watching two of you explaining TCP basics in wonderful way. Would like to see you both covering TLS as well. Fingers crossed 🤞

[@CrashLoopBackOff-K8s]

Adding a comment and like for the algorithm. I also subscribed to Chris. Great conversation and examples. More of this, please. As a reminder, your audience not only includes those just beginning their networking careers, but also those like myself who are professionals in other areas and need to pick up enough skills to be competent in some of the areas you focus on. Your content is appreciated, David.

[@tomsgrinbergs8020]

You definitely got to continue with this type of content, cheers Chris for this. Really good bunch of notes I've made on my side!!

[@erezcohenbox]

Thank you for letting me listen to your conversation! I have learned a lot. Great job.

[@Zerback]

Thank you very much for going at this level. You are helping a lot of people that just starting on the networking/ security side of computers. Please continue going deep with different types of protocols!

[@tz2014]

Awesome, it is even more interesting when David fires up some questions to help us understand the concepts well. Chris really knows his stuffs

[@kevinlong3147]

Thank you so much David and Chris, this was very eloquently taught. I had a better time understanding here than my ccna classes.

[@kshitijpatil4145]

Thanks for the series David & Chris this deep dive session is really amazing, took 1 hour of my time but would love to utilize more than that for future deep dive episodes as it is really interesting to learn. Considering TCP would like to learn examples with TCP flags RST, PSH, URG also if we use NAT & PAT how the other TCP header info will affect for the actual source & destination systems.

[@Jason.Detrick]

I'm studying for my CCNA and I need all the help and insight I can get for each of the layers of the OSI / TCP model. Learning about the handshake and the behind the scenes down into the raw numbers and why the packets are what they are and how each client frames up the numbers is great, so thank you! I'd love as much real life troubleshooting as I can get, down to why each possible problem might end up showing itself. It can be overwhelming for sure and just reading about it can be so dry it's hard to hold the knowledge but with video examples like this I believe it will help a lot.

[@andriejusartamonovas1857]

so simple, so clearly explained, yet so hard to digest... I guess I've found something I will enjoy grinding on! thank you!

[@tomhartley5086]

Awesome video David and Chris, your collaborative videos are awesome and very helpful!! MORE PLEASE :)

[@themistoclesnelson2163]

Enjoyed the deep dive. Came for the window, but watched the whole thing.

[@cryptoknight5927]

Thanks a lot for both you two David and Chris that's what we really want as it's a simplifying the heavy manual books information and move many student from beginner level to the top

[@JMalikZ]

Never seen someone dissect TCP handshake like this. Amazing!

[@Visualicon]

This is Great!! I used to have my CCNA way back and was never taught in this deep about TCP/IP aside from SYN/ACK and Sliding window. along with Latency it really makes more sense how payload is transferred and the TCP issues that can some along with it.

[@Addy580]

This really made my 1 hour journey back to home from office fun, thanks 🙏

[@oumadahmed4625]

Just discovered your channel and I’m so happy I did. Your work is a masterpiece

[@Sherloklol]

This was some of the best tcp/wireshark education i've seen where you simply things so it's understood. well done and thank you

[@chillarn7]

Amazing video, learned a lot! It really helps seeing the packet captures to fully grasp the TCP concepts.

[@jindalabhishek1]

Hey David and Chris, Thanks for sharing and giving back to the Community!!!. I will follow your path and share as much as I can

[@ajaykhanna1981]

Awesome Stuff, so insightful !! Thanks Chris and David. I loved the way David keeps on countering Chris and Chris very calmly and brilliantly knocking it out of the park.

[@shokijames]

Chris you explained everything so good that I went straight to your channel and subscribed. Thanks to both of you

[@foi50]

hello there, i'm from france and your video motivates me to become a great network engineer thank you sm

[@jm-nn4fz]

Cris and David you are real educators and no starch material on this channel 👌

[@StanleyLoh]

as a dual CCIE i still find this very useful and informative. recommended it to everyone in my team.

[@arorarachit]

hey david, awesome stuff. cant wait for this we need the continuation of this series!!

[@lakiluci474]

I decided to not watch this Video when i saw it's too lengthy , but today, due to some Un-stable situation in Africa , i got off from my Work, & Watched the Video , it really helped me

[@deivids4221]

What an amazing video. Thank you to both and I hope there will be more to come. This is very well explained and put together.

[@northblue8216]

Wow!! Fantastic stuff. Do you know, my life just flashed before my eyes.... A+, Network+, This video series, then CCNA!

[@wasid7678]

you never disappoint your students David neither with your tutorials nor with your guests .. Keep doing this awesome work _V_

[@rakeshcristobal8320]

Great detailed look into TCP with Chris! Looking forward to more videos with Chris!

[@mrmike81818]

Found a little gem with this video and I've never seen such a breakdown. Wireshark seems so much simpler now. I'm looking forward to taking networking to the next level with you guys, thanks!

[@chandramohanr2000]

This is a great session!! Got a lot of insights around the TCP. Thanks David for arranging this session!!

[@powellthepog5624]

The explanation for the sequence number (raw) was a life saver!

[@jacobhenriksen2324]

Absolutely LOVE this! Can't wait for the rest of the series!

[@robertprice7459]

Brilliant explanation by Chris, big thank you to Chris and David. Can't wait for the next instalment

[@chfstudio]

Wow! Very clear and powerful explanation! Thank you for this lesson!

[@Shalom_Mike]

Wow! Great video for non-network admins too. 😃 Can't wait for more! The subject matter was explained perfectly! Even I understood it!

[@jozefwoo8079]

Love these deep dives David! Would love some on authentication protocols as well! And apart from that thank you so much for all that great content, you are such a force of good in the world! It touches my heart! Great guest! Edit after finishing the video : this is amazing content!

[@paulifea7072]

Great video and great explanation by both parties, like all other commenters have mentioned is a really valuable discussion. From the window scaling factor provided by the server (512), I assumed that all packets sent from the client to the server and vice versa would stick to the window scaling size of 512. But from inspection in the provided pcap file, the client remained the window scaling size of 64 (as indicated in the options header of the client SYN packet) while the server continues to send packets with the scaling factor of 512. Hope this clarifies anyone's doubts on the window scaling size of both client and server. Both of you have been so resourceful I'm so happy for this series.

[@pedrocosta8846]

wow! i wish UNIs had teachers explaining subjects like this! Thank you

[@davidbombal]

Glad you enjoyed the video Pedro!

[@pallavi8388]

Thank you David, this is soo interesting and informative. Finally i got to know what happens in 3way handshake. Until now i just thought SYN SYN ACK ACK. Chris explains everything in such a detailed manner just love his explanation.

[@MrBitviper]

awesome content as always david. I love watching these thoughtful discussion collaborative videos that you have on your channel. we learn so much from you would be awesome to see a deep dive into quic as well.

[@nahleaky586]

This was a great overview of the TCP/IP part of a networking class I took in university. Well done!

[@yggdrasil6787]

As a french student, I would like to thank you for providing me with a way to both improve my English listening skill and my general IT knowledge 😁 Keep it up!

[@maheshsudarsi82]

many training institutes are not not teaching these underlying concepts. Great work and thank you...

[@nilesh.mohekar]

I once was asked about the tcp flags during an interview which I couldn't quite answer, now I have learned about them :) Thanks for the great content!!

[@HollowGrey]

Great video, thank you for sharing. A lot of great takeways for troubleshooting. Also, awesome analogy with water representing throughput. It was explained very well.

[@cd.8749]

Thanks guys, you both nailed it, and I learned a lot ! Really good questions by david and very illustrated and precise answers by chris !

[@dushyantsinghshekhawat969]

You are doing very great by providing free knowledge to everyone. And the content is also superb.

[@davidbombal]

Thank you!

[@gtsui87]

Absolutely love this content. Most content that are on the web that pertains to tcp are explained in a very complex way. I love how Chris makes this very dumb down for the average person looking to learn tcp. Please continue this series as its very interesting and provides invaluable knowledge.

[@ChrisGreer]

I try to explain the way my brain processes things - so I gotta keep it simple! :-)

[@rhinners3407]

Love the practicality side of this... Why are these numbers important, and how to use them to troubleshoot. How and Why!

[@Bharath-wb8uy]

Thank you buddy I love all your episodes and thank you for creating a playlist with all of Chris's videos