From owner-freebsd-net Wed Dec 19 8:49:28 2001 Delivered-To: freebsd-net@freebsd.org Received: from comp.chem.msu.su (comp-xl.chem.msu.su [158.250.32.157]) by hub.freebsd.org (Postfix) with ESMTP id A30D637B405; Wed, 19 Dec 2001 08:49:19 -0800 (PST) Received: (from yar@localhost) by comp.chem.msu.su (8.11.1/8.11.1) id fBJGn3l31461; Wed, 19 Dec 2001 19:49:03 +0300 (MSK) (envelope-from yar) Date: Wed, 19 Dec 2001 19:49:03 +0300 From: Yar Tikhiy To: Maxim Konovalov Cc: net@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: Processing IP options reveals IPSTEALH router Message-ID: <20011219194903.D21732@comp.chem.msu.su> References: <20011219181929.A20425@comp.chem.msu.su> <20011219190533.W57795-100000@news1.macomnet.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20011219190533.W57795-100000@news1.macomnet.ru>; from maxim@macomnet.ru on Wed, Dec 19, 2001 at 07:23:55PM +0300 Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Wed, Dec 19, 2001 at 07:23:55PM +0300, Maxim Konovalov wrote: > > > I ran into an absolutely clear, but year-old PR pointing out that > > a router in the IPSTEALTH mode will reveal itself when processing > > IP options: kern/23123. > > > > The fix proposed seems clean and right to me: don't do IP options > > at all when in the IPSTEALTH mode. Does anyone have objections? > > If no, I'll commit the fix. > > First of all we should decide what IPSTEALTH is for. Is it just a > Ruslan's net.inet.ip.decttl or it should really stealth the fact of > the routing? If the latter how do we behave in source routing case? Are there any reasons for a router not to decrement IP TTL besides trying to stay invisible to a third party? 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. -- Yar To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message