From owner-freebsd-security Wed Oct 31 5:36:57 2001 Delivered-To: freebsd-security@freebsd.org Received: from ibb1150.ibb.uu.nl (ibb1150.ibb.uu.nl [131.211.125.150]) by hub.freebsd.org (Postfix) with ESMTP id F29EF37B401 for ; Wed, 31 Oct 2001 05:36:53 -0800 (PST) Received: by ibb1150.ibb.uu.nl (Postfix) id 6B3C143B9; Wed, 31 Oct 2001 14:36:33 +0100 (CET) Date: Wed, 31 Oct 2001 14:36:33 +0100 From: Mipam To: Michael Scheidell Cc: freebsd-security@FreeBSD.ORG Subject: Re: can I use keep-state for icmp rules? Message-ID: <20011031143633.E397@ibb1150.ibb.uu.nl> Reply-To: mipam@ibb.net References: <009c01c16017$dca045d0$0603a8c0@MIKELT> <20011029153954.B224@gohan.cjclark.org> <005501c1613f$dfb46520$0603a8c0@MIKELT> <20011030164253.C223@gohan.cjclark.org> <000901c1620f$51428530$2801010a@MIKELT> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <000901c1620f$51428530$2801010a@MIKELT>; from scheidell@fdma.com on Wed, Oct 31, 2001 at 08:24:05AM -0500 X-Operating-System: BSD Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org > > TCP > > src_ip.src_port ----> dst_ip.dst_port > > > > I can send _any_ TCP packet back, > > > > TCP > > src_ip.src_port <---- dst_ip.dst_port > > > > And it will pass provided the source and destination IP and ports all > > line up. ipfw(8) does not consider the TCP flags, sequence number, Bit off topic, but nowadays still a lot of so called 'best' and great commercial firewalls still dont check the sequence number for example. Would be good enough for udp state keeping in a way, but not for tcp. Not to mention icmp statekeeping which still isn't possible in many products. Mipam. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message