Posts Tagged With ‘troubleshooting’

1. The Megalodon Challenge

   This year at Sharkfest I offered a special capture file challenge I called “The Megalodon Challenge”. Other than the “normal” challenges you could find at The Reef it was not limited to the size of 100MB, and the solution cannot be reduced to a couple of words or numbers. After Sharkfest I was asked if […]

2. Zombie Packet Mayhem!

   My previous post was about one of multiple false positives a network analyst needs to keep an eye out for to avoid writing down findings in a report that weren’t really there. So when I looked at my Sharkfest traces to see what other topic I could write this post about I realized that I […]

3. Diagnosing intermittent “network” problems

   There’s that one thing that customers usually ask, and that question is if I would be able to help diagnosing a problem on the network. My answer has two parts: If we can capture the problem situation in packets, I will find it When I find it, I’ll tell you if it’s a network problem […]

4. TCP Server slamming the door

   After doing a lot of analysis sessions on TCP connections there are some patterns that you see again in a trace every once in a while. And often it comes in handy to remember what the situation was and what the circumstances were that led to the trace showing what it did.

5. Spurious Retransmissions

   Update: since Wireshark version 1.12 is out, lots of people look for the meaning of “tcp spurious retransmission” info message, so I changed the post a little to make it easier to find what you’re looking for. Today, while doing a lot of testing of my trace handling code as well as in preparation for […]

6. Firewall trouble

   A few days ago my connection(s) to the computing center suddenly degraded, meaning that I suddenly could not contact some of my servers anymore or only after waiting for sometimes minutes, while others worked fine. I checked the Icinga monitoring system and saw that everything was fine, except the firewall, which seemed to have a […]