Re: tcp sequence and ack number with libpcap

[Andrej van der Zee <andrejvanderzee () gmail com>]

Hi,

If I get "bad cksum 0 (->4327)!" for packets with "tcpdump -vv" like below,
do I have to take special measures to read fields like seq and ack from the
TCP header?

17:55:47.657974 IP (tos 0x0, ttl 128, id 13151, offset 0, flags [DF], proto
TCP (6), length 1420, bad cksum 0 (->4327)!)
    172.16.123.4.80 > 193.34.150.174.38357: Flags [.], seq 1:1369, ack 436,
win 65100, options [nop,nop,TS val 53409804 ecr 3029480193], length 1368

Thank you,
Andrej
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