From: Pascal Hambourg <pascal.mail@plouf.fr.eu.org>
To: Alec Matusis <matusis@matusis.com>
Cc: netfilter@vger.kernel.org
Subject: Re: PREROUTING DNAT *inconsistent* behavior
Date: Sat, 18 Dec 2010 01:15:09 +0100 [thread overview]
Message-ID: <4D0BFD0D.2070406@plouf.fr.eu.org> (raw)
In-Reply-To: <06c201cb9e46$b4d13560$1e73a020$@com>
Alec Matusis a écrit :
>> I would have used DNAT instead to make sure
>> the destination address is not changed.
>
> Instead of REDIRECT, we used:
> -A PREROUTING -d server.ip -p tcp --dport 443 -j DNAT --to-destination
> server.ip:5228
> The result is exactly the same.
Do you mean that REDIRECT did not alter the destination address when it
was different from the primary address on eth0 ?
>> What are the other 5% then ?
>
> They are mostly RST packets from various clients:
Sure, RSTs are sent in reply to the bogus packets from the servers.
>> They are probably packets classified in the INVALID state by the
>> connection tracking, which are ignored by the nat table. In a NAT
>> setup,
>> INVALID packets should be dropped because of this. Now the real
>> question
>> is : why are they classified in the INVALID state ?
>
> How can I verify that these packets have been classified as in the INVALID
> state? That may be the key to this problem.
As I suggested, DROP packets in the INVALID state. If you don't see them
any more, you'll know.
next prev parent reply other threads:[~2010-12-18 0:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-15 4:42 PREROUTING DNAT *inconsistent* behavior Alec Matusis
2010-12-17 22:20 ` Pascal Hambourg
2010-12-18 0:01 ` Alec Matusis
2010-12-18 0:15 ` Pascal Hambourg [this message]
2010-12-18 1:55 ` Alec Matusis
2010-12-20 21:05 ` Pascal Hambourg
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