Troubleshooting Loops: IPv4 ID/TTL and Addressing Notes Before I start, let the first cover a very common question I get asked. I will not be providing vendor specific information on this troubleshooting example. Nor will I be sharing the trace file. The goal of this article and video, is to introduce you to the methodology, tips and tricks, and other things that you may not have thought of when you perform protocol analysis. On to the problem; I covered a little bit about this in previous articles when I was talking about making a larger trace file manageable. The client is complaining that the network has performance brownouts and wireless clients tend to get dropped off. So, I asked them to connect his computer to any port on that same deal and start a capture for a few minutes and then stop it, and send it to me. I then filtered and the capture device’s traffic and will go through the remaining packets and this exercise. In the video you will see how I leverage the IP identifier, time to live and MAC addresses to determine what is happening. When I present or teach, I stress the goal of troubleshooting is to either prove what the issue is NOT or to figure out where your test point is with the final target being identifying the root cause. Spoiler alert, the high packet rate of small broadcast packets is causing the problem. ... https://www.youtube.com/watch?v=iLaGKdri3Wc

This is a pretty neat little utility that will record what you download/run when you go to a website site as well as how long it took. Linkedin Profile http://ca.linkedin.com/in/fortunat Lovemytool Blog: http://www.lovemytool.com/blog/tony-fortunato/ Youtube Channel: http://www.youtube.com/user/thetechfirm ... https://www.youtube.com/watch?v=EC4iaHNr-0E

Troubleshooting WiFi Issues with Wireshark A customer called me and wanted some help troubleshooting some wireless problems. Their users have been reporting intermittent wireless performance issues and getting 'dropped'. To top it all off their WLAN controller has also been reporting 'containment' error messages that weren't to descriptive or helpful. I showed up on site and did all the basic RF checks with my AirMagnet Spectrum XT to make sure there wasn't an RF issue like an interferer or channel planning issues. Like I always say, "Start at Layer 1". Then I moved up a layer using my Fluke Networks AirCheck and AirMagnet WiFi Analyzer. Everything looked pretty quiet and nothing jumped up at me, so I saved some trace files to review later. When I thought I would take the trace file and open it with Wireshark since I have more experience with packet analysis than I do using the AirMagnet/AirCheck tools. In this video I show you some of the filters I used, what they mean and what I found. I always enjoy getting to the packet level since packets don't lie, but would also like to spend more time with the other tools now that I know what issues are to see how or what they report. In closing there are a few points I want to make sure aren't lost throughout the video; 1. Just because I used Wireshark to find some clues does not mean that the other tools were less effective, I just have more experience with protocol analysis/Wireshark. 2. If you deploy any kind of wireless intrusion system, make sure you don't just turn it on without proper network due diligence. Linkedin Profile http://ca.linkedin.com/in/fortunat Lovemytool Blog: http://www.lovemytool.com/blog/tony-fortunato/ Youtube Channel: http://www.youtube.com/user/thetechfirm ... https://www.youtube.com/watch?v=rpL5irIj_Qo

By Tony Fortunato, Sr Network Performance Specialist, The Technology Firm – https://www.thetechfirm.com Working on an issue with a client where his VOIP phone’s get stuck at the ‘initialization’ process. As we chatted over the phone we quickly determined that this issue occurs when a phone is powered off and back on. The client also mentioned that this seemed to start about a year ago when they got a new router installed. I asked how he typically resolved the issue and he said “I just reboot stuff until everything works”. I have to give him credit, at least he was honest. Just a few things I checked when I got on site: - Yup, the problem is definitely repeatable which is a huge plus when troubleshooting. - Verified that the phone had a link light - Phone reports that it has ... https://www.youtube.com/watch?v=ylj7ER9PUBU