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Date:      Sun, 23 Dec 2001 02:29:14 +0300 (MSK)
From:      Maxim Konovalov <maxim@macomnet.ru>
To:        Yar Tikhiy <yar@FreeBSD.ORG>
Cc:        net@FreeBSD.ORG, <hackers@FreeBSD.ORG>
Subject:   Re: Processing IP options reveals IPSTEALH router
Message-ID:  <20011223022614.U18529-100000@news1.macomnet.ru>
In-Reply-To: <20011221185118.B25868@comp.chem.msu.su>

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Hello,

On 18:51+0300, Dec 21, 2001, Yar Tikhiy wrote:

> On Wed, Dec 19, 2001 at 08:54:50PM +0300, Maxim Konovalov wrote:
> > On 19:49+0300, Dec 19, 2001, Yar Tikhiy wrote:
> >
> > > As for source routing, I believe a stealthy router should just drop
> > > such packets as though it were a host.  Of course, source-routed
> > > packets destined for the router itself should be accepted.
> >
> > So there are three IPSTEALTH cases:
> >
> > 1/ the dst address is not ours, net.inet.ip.sourceroute=0,
> > net.inet.ip.forwarding=1: process ip options by ip_dooptions().
> >
> > 2/ the dst address is ours: process ip options by ip_dooptions(),
> >
> > 3/ in other cases do not process ip options.
>
> I made a patch that adds the "stealthy IP options feature".
> Honestly, now I'm afraid it's "much ado about nothing", given how
> clumsy solution is needed for such a small problem.  Even the way
> of ignoring IP options completely when doing IPSTEALTH looks way
> better...

IMHO it is not a good idea to forward a packet with possible incorrect
ip options.

The patch looks OK for me.

-- 
Maxim Konovalov, MAcomnet, Internet-Intranet Dept., system engineer
phone: +7 (095) 796-9079, mailto: maxim@macomnet.ru


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