254 bytes tcp window size setting

asked 2024-10-26 06:33:57 +0000

avis
1

Hi, I am troubleshooting network and faced a lot of 'TCP zero window' during TDS sessions , which advertising by the dominate server in the service. Start digging in ,I noticed that the server advertised constant 254 bytes TCP window size. I checked its paired servers and notices the same ... They as well advertise low tcp window size.

From your experience what coud cause such setting (limiting the throughput in purpose... )?

The VM setts to 4 cores and 2 CPU's in order to try eliminate CPU ready picks of 95 % Memory :30Gbyte CPU : 8*2GHz

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answered 2024-10-26 08:00:47 +0000

SYN-bit

18528 ●9 ●339 ●255 https://SYN-b.it

Usually a window size of 254 is an indication that the three-way-handshake was not captured and thus the window scaling factors are unknown. This means Wireshark can only show the value of the window size field value, instead of the really used size of the window. Sometimes the traffic pattern can give an idea on what the scale factor must have been and then you can set that in the TCP protocol preferences.

It is better though to make sure the 3-way-handshake is also captured, makes life a lot easier :-)

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Asked: 2024-10-26 06:33:57 +0000

Seen: 97 times

Last updated: Oct 26

254 bytes tcp window size setting edit

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