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From: Henrik Nordstrom <hno@marasystems.com>
To: don-nf@isis.cs3-inc.com (Don Cohen), netfilter-devel@lists.samba.org
Subject: Re: Syncookie firewall
Date: Wed, 5 Jun 2002 21:38:14 +0200	[thread overview]
Message-ID: <200206052138.14928.hno@marasystems.com> (raw)
In-Reply-To: <15614.26348.278645.301276@isis.cs3-inc.com>

Don Cohen wrote:

> There are some tcp options that have to be sent in the syn packet,
> e.g., window scale.  These become unusable if this packet is supplied
> by the firewall, unless the firewall somehow knows how the original
> destination host "would have" answered.  This seems unfortunate, and
> I don't see a good solution.

Not to mention that there is TCP options a firewall cannot know, such as the 
timestamp option.

In my opinion, If you do "syncookie" in a firewall then the TCP should be 
terminated there, with another TCP in to the real server. I.e. a proxy 
solution.

Regards
Henrik Nordström

  reply	other threads:[~2002-06-05 19:38 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20020603132204.7934546FF@lists.samba.org>
2002-06-05 19:30 ` Syncookie firewall Don Cohen
2002-06-05 19:38   ` Henrik Nordstrom [this message]
     [not found] <20020606192927.6B7684DCE@lists.samba.org>
2002-06-06 21:18 ` Don Cohen
2002-06-06 21:34   ` Henrik Nordstrom
2002-06-06 22:03     ` Mark Atwood
2002-06-06 22:36     ` Don Cohen
     [not found] <20020606020322.05BF64258@lists.samba.org>
2002-06-06 16:28 ` Don Cohen
2002-06-06 17:32   ` Henrik Nordstrom
2002-06-07  9:21     ` Michel Banguerski
2002-06-07  9:47       ` Michel Banguerski
2002-06-07  9:56       ` Henrik Nordstrom
2002-06-02 18:47 Michel Banguerski

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