From: "David S. Miller" <davem@redhat.com>
To: Nathaniel M Nelson <nmn@chartermi.net>
Cc: netdev@oss.sgi.com
Subject: Re: Possible weird TCP bug
Date: Tue, 13 Jan 2004 16:01:35 -0800 [thread overview]
Message-ID: <20040113160135.45cc677d.davem@redhat.com> (raw)
In-Reply-To: <3FFE2B00.2030607@chartermi.net>
On Thu, 08 Jan 2004 23:16:00 -0500
Nathaniel M Nelson <nmn@chartermi.net> wrote:
> 0000 00 02 7d 66 a4 54 00 e0 81 23 14 78 08 00 45 00 ..}f.T.. .#.x..E.
> 0010 00 3c 9a 41 40 00 3f 06 f4 1f 18 e7 92 21 d8 ef .<.A@.?. .....!..
> 0020 29 63 89 37 00 50 e5 4b 22 e0 00 00 00 00 a0 02 )c.7.P.K ".......
> 0030 16 d0 36 6a 00 00 02 04 05 b4 04 02 08 0a 03 1d ..6j.... ........
> 0040 b8 a1 00 00 00 00 01 03 03 00 ........ ..
>
> Then after I get the SYN,ACK back, the firewall will send out the next
> ACK with the sequence number correctly incremented by 1.
>
> 0000 00 02 7d 66 a4 54 00 e0 81 23 14 78 08 00 45 00 ..}f.T.. .#.x..E.
> 0010 00 28 9a 42 40 00 3f 06 f4 32 18 e7 92 21 d8 ef .(.B@.?. .2...!..
> 0020 29 63 89 37 00 50 e5 4b 22 e1 db f2 5c c5 50 10 )c.7.P.K "...\.P.
> 0030 16 d0 21 3d 00 00 ..!=.
>
> So of course the sequence is "1" in that packet. Both sequence numbers
> seem a little low though... and not very cryptic. If this is not a bug
> I apoligize in advance.
In the initial packet, the only zero is the "ACK" sequence, when the first SYN
goes out we don't know the starting sequence number the other side will
decide to use so we set that field to zero (and also the ACK bit is clear in this
packet which makes the ACK sequence field not valid anyways).
This dump looks perfectly fine to me.
prev parent reply other threads:[~2004-01-14 0:01 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-01-09 4:16 Possible weird TCP bug Nathaniel M Nelson
2004-01-14 0:01 ` David S. Miller [this message]
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