SMB2 5354 [Illegal Segments]

asked 2024-12-04 15:23:42 +0000

updated 2024-12-04 16:49:17 +0000

grahamb gravatar image

Packet:

3126    0.830669    192.168.0.11    192.168.0.17    SMB2    5354    [Illegal Segments]

Does anyone know what this can indicate? We have a virtual Win2019 doing backup to a Synology NAS which recently has been failing at random places in it's backup procedure.... could be 20GB in or 600GB in. The backup software fails with a write to UNC file error (not the exact error). I have tried switching the backup destination to another NAS and then it runs fine.

I can see in the pcap file that after the above message the two IPs exchange words there are some keep alive traffic and then eventurally the source IP sends a reset.

I was thinking initially that it was a storage problem but I am not sure now, only thing I have to go with is this [Illegal Segments] error that the source IP sends after 4 normal looking TCP PDU reasemble messages. Is it a source or destination error, I can't tell as I am not very good at Wireshark.

Any help would be greatly appreciated.

Best Thomas

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