It hurt my back, but nothing some scotch couldn’t fix.ĭownload the pcap Share this post! Spread the packet gospel! I meant to slowly slide out of my chair in the beginning but fell somehow.TCP will ACK every packet when in recovery.ACK number tells you what data has been received and what the next received sequence number should be.Next sequence number is sequence number plus TCP data payload length.Add sequence number, next sequence number, and acknowledgment number to your Wireshark columns.The Wireshark Expert Info is just a guide, you need to be able to determine if it’s trustworthy and correct.

If you’re going to learn packet analysis, it is key that you understand what sequence numbers are for and be able to follow the action in the capture as it relates to the stream of data being tracked by those sequence numbers. This video will show an example of a scary looking section in a capture and walk through exactly what’s going on and if it’s a problem or not. Well, you know all those black and red packets in Wireshark? Sure, you’ve seen them, right? Scary, huh? What if someone says there’s a problem and you see a bunch of those packets in Wireshark. But more importantly, WHY you should do TCP sequence number analysis.

Wireshark tcp retransmission filter