From: Emmanuel Guiton <emmanuel@netlab.hut.fi>
To: Henrik Nordstrom <hno@marasystems.com>
Cc: netfilter-devel@lists.netfilter.org
Subject: Re: NAT breaks my TCP SYN/ACK?
Date: Fri, 19 Dec 2003 11:21:40 +0200 [thread overview]
Message-ID: <3FE2C324.6010902@netlab.hut.fi> (raw)
In-Reply-To: Pine.LNX.4.44.0312161850090.3671-100000@filer.marasystems.com
Hei!
Sorry for my late answer, I wasn't really at work these last days.
Henrik Nordstrom wrote:
>On Tue, 16 Dec 2003, Emmanuel Guiton wrote:
>
>
>
>>In my tests, I'm trying from a host at adress X to reach a website at
>>address Y. However this website does not exist on that address but on
>>address Z. Thus, basically in my target, I change address Y for Z. But
>>the connection to the website is refused, and tcpdump shows the following:
>>
>>17:25:21.568709 11.11.11.10.1262 > 10.10.10.10.www: SWE
>>1338652779:1338652779(0) win 5840 <mss 1460,sackOK,timestamp
>>8306468[|tcp]> (DF)
>>17:25:21.569136 10.10.10.10.www > 11.11.11.10.1262: R 0:0(0) ack
>>1338652780 win 0 (DF)
>>
>>
>
>What does tcpdump on the "website" indicate?
>
>My quess is that the port is not mapped correcly causing the SYN to hit
>another port on the server than you intended.
>
>
You are right, I gathered a few more data and that's it:
11:12:41.535710 11.11.11.10.1266 > pc104.4: SWE 2321994237:2321994237(0)
win 5840 <mss 1460,sackOK,timestamp 31990183[|tcp]> (DF)
11:12:41.535941 pc104.4 > 11.11.11.10.1266: R 0:0(0) ack 2321994238 win
0 (DF)
The port here is 4 instead of being 80. I'm going to investigate this.
Thanks,
Emmanuel
prev parent reply other threads:[~2003-12-19 9:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-16 15:41 NAT breaks my TCP SYN/ACK? Emmanuel Guiton
2003-12-16 17:51 ` Henrik Nordstrom
2003-12-19 9:21 ` Emmanuel Guiton [this message]
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