For those of you who are unfamiliar with NMAP, you can perform a subnet scan using any of the 3 following options, subnet/mask, IP address range, IP address and * wildcard. For example, on my network it would look like something like this; 10.44.10.0/24 or 10.44.10.1-254 or 10.44.10.*
As I was performing the scan, I was explaining that you should always ‘know your tool’ by simply performing a packet capture. I went on to say that all you have to do is start, stop and save your capture with a descriptive name. So even if you did not have time to go through it now, or go through it thoroughly, its there for future reference.
In this video I should you some of the NMAP behavior we spotted. First thing we noticed was that NMAP performed a discovery using an ARP scan, then it used DNS reverse name lookup to determine the host names. This is where we go down a bit of a rabbit hole. I noticed that my computer was communicating with the correct DNS servers, but then went off and communicated with 2 other IP addresses.
I put this video together to share a hands-on look at the technology I’ve been experimenting with in my own home lab. Rather than reading through specifications or marketing claims, I wanted to show the actual setup, configuration process, and the results I saw during testing. My goal was to make the video feel like a real lab session where viewers can follow along and see both the successes and the challenges that come with working on networking and server projects.
As I walk through the setup, I explain not just what I’m doing, but why I’m making certain configuration choices. I’ve learned that understanding the reasoning behind a setting is often more valuable than memorizing a series of clicks or commands. Whether it’s networking behavior, system configuration, or performance tuning, I try to break the concepts down in a way that is easy to follow without oversimplifying the technical details.
One thing I intentionally included was the troubleshooting process. In real IT environments, things rarely work perfectly the first time, and I think showing those moments makes the content more useful and more honest. I talk through the issues I encountered, the tests I ran, and the adjustments I made to get everything working properly. That practical problem-solving aspect is often where I learn the most, and I wanted viewers to benefit from that experience as well.
I also wanted the video to encourage experimentation. Seeing the commands, settings, and results in real time gives a much clearer picture of what is happening behind the scenes. If someone has a home lab, a spare server, or networking gear sitting on a shelf, I hope this video inspires them to power it up and start testing ideas of their own. Technology becomes much more interesting when you can interact with it directly.
Overall, this video reflects the kind of technical content I enjoy creating: practical, hands-on, and focused on real-world results. I came away from the project with a few new ideas to explore, and I hope viewers do as well. If you enjoy networking, servers, virtualization, Docker, or home-lab projects, I think you’ll find something useful in this walkthrough, and I’d love to hear about the setups and experiments you’re working on too.
In the video I show you how I figured it out and then how NMAP used the same TCP return port number for its port scans.
