Have a question about networking or computing? Hopefully you can find an answer here!
Frequently asked questions about the CellStream consulting and training services are answered here as well as number of other topics. If you would like to ask us a question, it is easy to contact us.
We hope you find the content here useful.
A great question in my two day Security class recently. The physical layer (Layer 1) of the layered model is responsible for the transmission of raw data bits over a communication medium. Although it is often considered more secure due to its reliance on physical components, it is still vulnerable to a variety of threats. […]
What are some examples of Physical Layer Threats in Networking? Read More »
I am getting asked a lot about this. Below is mix of reporting and my take on what happened and what needs to be done. Just so we are clear: I have no secret inside knowledge or insight into the problems. But if you are looking for a clear explanation, read on. The recent CrowdStrike
What was the nature of the July 2024 CrowdStrike computer outages? Read More »
Network Address Translation (NAT) and Network Port Address Translation (NPAT) are not considered a security function because its primary purpose is to modify the L3 network address information in IPv4 packet headers and L4 port numbers of TCP or UDP while in transit. NAT and NPAT are not needed in IPv6 networking. NAT is primarily
Why are NAT/NPAT not a security function? Read More »
Someone asked the following “getting started” question on the Wireshark Discord site, and it prompted me to write this FAQ to help newcomers to Wireshark understand how to navigate the initial complexity of packet capture. Hi everyone! I’m new here and just downloaded wireshark for a Computer Comm class. I need to capture traffic sent
A Simple Capture and Filter Exercise for Wireshark Read More »
Asynchronous Transfer Mode (ATM) was once seen as a promising Layer 2 networking technology due to its ability to handle a variety of traffic types (voice, video, and data) with high efficiency and quality of service (QoS) performance guarantees. I spent several years working with and then teaching ATM courses to my fellow telecom engineers.
What ever happened to ATM (Asynchronous Transfer Mode)? Read More »
As always seems to be the case, there are several ways to find the MAC (Media Access Control) address of your interfaces in Windows. I am going to try to make this easy and considerate of different versions of Windows out there. Using the Command Line To find the Windows MAC address from Command Line,
How do I find my PC’s MAC address on Windows? Read More »
I am often asked this question of where to access PCAP or PCAP-NG files so that folks can explore packet captures using Wireshark. I have always provided these resources in my Wireshark classes at the Online School, but thought I should also just list them here for public consumption. Look up the hashtag “captureeveryday” in
Where can I get PCAP Packet Captures for Learning and Exploration? Read More »
How do I install / upgrade Wireshark in Ubuntu Linux? First things first – the Wireshark downloads page is here: https://www.wireshark.org/download.html I know I have put the answer to this in other articles over the years (like this one), but I think it is appropriate to answer the question directly and specifically. Installing Wireshark in
How do I install / upgrade Wireshark in Ubuntu Linux? Read More »
Check out these great references as well: Our custom profiles repository for Wireshark Our Udemy course on Wireshark Our Udemy course on Wireless Packet capture Apparently this is a common problem, where on Windows systems you do not see any interfaces: There are a couple of things to try: 1. If you are using the
How do I get Windows interfaces to show up in Wireshark? Read More »
I was recently asked the question “If I want to get into Networking, what should I learn?” A great question because Telecommunications or Data Networking is really not a degree program at most universities, at least not at the undergraduate level. There are some masters programs, but they are few and far between. In fact,
If I want to get into Networking, what should I learn? Read More »
This is a great question recently asked by one of our students/clients when we said our ususal introductory comments that “No we won’t spam you”, and “No we don’t use the click model on our sites”. Let’s talk spam. We have never spammed our students/customers and we have an anti-spam policy. You are automatically
Why don’t you employ the “click” model on your sites? Read More »
This question (really two questions) has been popping up quite a bit lately. Let me see if I can explain. First, let’s define what SD-WAN is. SD-WAN leverages the SDN concept of separating the control plane from the data plane and creating a controller running software that can enact control and policies on the network.
What is SD-WAN? Does it replace MPLS? Read More »
This is a great question, and there is a building pile of learning SDN courses out there. Perhaps the most technical one we found, we loved, and thanks to the great folks at Georgia Tech, the lectures were placed in the public domain. We assembled those video lectures and added our own quizzes and labs
Where can I learn SDN? Read More »
We get this question often: I am new to Telecom, or I just started at a service provider, and I need to learn Telecom basics – how can I come up to speed? This is a GREAT question – and the truth is: you need to get up to speed. The more you understand the
New to Telecom. How can I come up to speed? Read More »
