Author Archive for Jasper

  1. PCAP Split and Merge

    Sometimes it also happens during network troubleshooting engagements, but it is also common for analysis jobs regarding network forensics: dealing with huge number of packets, sometimes millions or more. Two typical situations may have you scratch your head: either you have one huge file containing all packets at once, or you have a ton of […]

  2. Wireshark GeoIP resolution setup V2.0

    I already wrote a blog post about setting up GeoIP resolution for Wireshark in 2013. Now, almost exactly five years later I had to decide if I replace that one with an updated version, or to write a second, updated post instead. I choose the second option.

  3. A look at Cisco Tetration

    Once again I was invited to join the group of delegates for Tech Field Day Extra at Cisco Live 2018 in Barcelona, with various presentations covering a number of new and improved Cisco technologies. One of them I had seen already last year at the same event in Berlin, but hadn’t had the time to […]

  4. The Network Capture Playbook Part 6 – Planning Network Troubleshooting

    In the previous posts of the Capture Playbook series we discussed various approaches about how to record packets, but before going into more elaborate techniques of doing that we should talk about how a network troubleshooting project works, and especially how to plan a capture setup. In my experience this aspect of a troubleshooting is […]

  5. Sharkfest 2017 EU Recap

    In 2017 the Sharkfest Wireshark user and developer conference happened once again in Europe – in the Hotel Palacio Estoril in Portugal, to be more specific.

  6. Sharkfest 2017 US Recap – 10 years of Sharkfest!

    Time always flies at Sharkfest, the annual Wireshark conference, and the 2017 edition – being the 10th Sharkfest in the US – has been no exception. On Friday Sake and me talked about how fast the 3 day conference had felt and we both agreed that “hm, it seems just to have started moments ago […]

  7. A look at Paessler PRTG

    During Tech Field Day Extra at Cisco Live Europe 2017 one of the presentations we attended was from Paessler, about their PRTG monitoring tool. I had only seen it once before, during a penetration test I performed at a customer site – and since it was running with default credentials it gave a very nice […]

  8. Programmable ASICs in Cisco Switches

    I know what a Cisco switch is. I know what an ASIC is – a processor designed for a special purpose that it can do it’s job faster than a generic purpose processor running the job in software. What I didn’t know is that it was also possible to build programmable ASICs.

  9. Network Forensics Playbook – Banner Inspection and Client Origin

    I recently did a hands-on-no-slides presentation at a very small security conference end of last year where I demoed some of the typical things I do when performing a network forensics analysis, using tshark, Wireshark and TraceWrangler. I’ll use these blog posts as a transcript of what I did, so that it’s easy to read […]

  10. The Network Capture Playbook Part 5 – Network TAP Basics

    Most network captures are recorded using SPAN ports, as we’ve seen in the previous part of this series. Now that we know what SPAN is all about, it’s time to find out what TAPs are all about, and why you would want (or need) to use them in network capture. TAP is an acronym for […]