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PiGeonCZ
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Posts: 12
Joined: Sat Jan 28, 2017 12:43 pm

packet sniffer streaming to wireshark = getting "previous segment not captured" error"

Sun Mar 26, 2023 3:36 pm

Hi there,
while doing some troubleshooting I wanted to avoid writing excesive amount of data to the Tiks flash, so used the packet sniffer streaming feature.
It worked quite well for most of the packets, but didn't for the ones arround the MTU size.
I write arround the MTU size above on purpose, because I am lost in the sizes/lengths of packet, frame, data and other things. :)

On the attached screenshot you can see there is the Fragment IP protocol packet on line 13, which is sent from Tik to my machine which most probably isn't complete thus wireshark is not able to reconstruct the capture and is complaining later (on the lines 15-17) about ACKed unseen segment.
There is also a pcapng file in the ZIP file if you want to look at it.
192.68.24.254 - My phone, trying to get a list of tuner presets in the Denon AVR app
192.168.24.48 - Denon AVR
192.168.24.1 - MikroTik
192.168.24.227 - My PC where Wireshark is receiving the sniffer stream

I am also attaching a screenshot with the MTUs of the interfaces.

Not sure what exactly is the reason, but maybe there is a way to fix this by tuning the MTU on my network.


thanks in advance for any help!

PiGeonCZ
RB4011 running on ROS v7.6
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