Understanding Duplicate ACKs in TCP: A Wireshark Walkthrough with Chris Greer

Unlock the Mystery of Duplicate Acknowledgments in TCP

If you've ever stared at a Wireshark capture wondering why you're seeing a flood of duplicate acknowledgments, this video by networking expert Chris Greer is exactly what you need. In this focused, no-fluff tutorial, Chris breaks down one of the most commonly misunderstood behaviors in TCP/IP traffic analysis — duplicate ACKs — and explains not just what they are, but why they appear and what they're telling you about your network.

Perfect for Troubleshooters at Every Level

Beyond Ping: Using TCP Connect, Traceroute, and Response-Time Graphing to Troubleshoot Network Connectivity

Ask any network pro about which command line tool they use the most – likely ping is near the top of the list, which makes sense. Ping has stood the test of time as a quick way to validate the network path between two endpoints.

But what if it fails? What can we do next?

When a ping is successful, we quickly can validate for at least that moment, we have a working path to the target station, routing is working, and basic connectivity is established. However, it is possible to have a successful ping even when underlying layer one and two issues are there - as these problems may not impact every single frame that traverses them.

The Canonical Weekend: Rethinking the 7-Day Week in the Age of Remote Work - Paul Smith

 

A former boss of mine had a well-rehearsed response for any employee who complained they had too much work. There are twenty-one 8-hr workdays in a week, he would say; three in each of the seven 24-hour days. If you are only using five out of those twenty-one, you are clearly just lazy.

Although the 40-hour workweek would be a dream come true for many (unless you happen to live in Luxembourg) , there are few among us who could ever envision working the 168 hours suggested by this guy. The average full time US worker puts in 41.5 hours, making us a nation of slackers by my old boss’s standards. The hardest workers are found in Colombia, where the average work week is nearly 50 hours, still less than a 30% utilization of available time. 

Layer 1 Troubleshooting: Common Physical-Layer Network Problems from Bad Cabling to Poor Installation

I thought it would be a good idea to start a series using the NetworkDataPedia’s theme of ‘knowing your network. 

Let’s start at layer 1 or the hardware layer.

Unfortunately, there is so much that can go wrong at this layer that I cant possibly cover it in one article.  I see a lot "you have a network connection and life will seem fine" attitude. This is unfortunate because if the problems would cause an complete outage, you would be forced to address it instead of ignoring it.

I find that many physical level issues are grouped into a few categories:

Installation and Support

FREE WIRESHARK CLASS - Lecture 5 - Hands on stuff

 

To celebrate my 10th year on youtube and to thank all those who watch, like, share and subscribe i wanted to give you a gift. 2 years ago i created a Wireshark class for Udemy which was very popular.