Ethereal-users: [Ethereal-users] Trying to understand ACK and SEQ numbers

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From: JS <fedevaps@xxxxxxxx>
Date: Tue, 20 Sep 2005 17:30:05 +0200 (CEST)
I have this print from a part of a session where a
client is uploading some text to a server. The client
is: 192.168.1.102 and the server is: 128.119.245.12.

In the part below the client starts sending seq 1 and
seq 565. Then the server responds with an ACK segment,
but how do I know which of the client segments this
ACK applies to?

In the last line I get another ACK from the server,
but again how do I find out which klient segment this
ACK applies to?? There are 4 klient segments but only
2 server segments.



192.168.1.102 / 128.119.245.12 TCP 1161 > www [PSH,
ACK] Seq=1 Ack=1 Win=17520 Len=565


192.168.1.102 / 128.119.245.12 TCP 1161 > www [PSH,
ACK] Seq=566 Ack=1 Win=17520 Len=1460


128.119.245.12 / 192.168.1.102 TCP www > 1161 [ACK]
Seq=1 Ack=566 Win=6780 Len=0


192.168.1.102 / 128.119.245.12 TCP 1161 > www [ACK]
Seq=2026 Ack=1 Win=17520 Len=1460


192.168.1.102 / 128.119.245.12 TCP 1161 > www [ACK]
Seq=3486 Ack=1 Win=17520 Len=1460


128.119.245.12 / 192.168.1.102 TCP www > 1161 [ACK]
Seq=1 Ack=2026 Win=8760 Len=0