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SYN-bit's avatar
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SYN-bit
answered 2022-08-29 22:11:36 +0000

The TCP checksum of frame 86 is incorrect, so the TCP/IP stack will discard it and therefor no ACK is sent for this segment. As the FCS of the ethernet frame is valid (otherwise the frame would have been dropped by the NIC), I suspect there is an error in your checksum calculation function that produces the wrong checksum value.