From owner-freebsd-hackers Mon Aug 14 16:23:29 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from jade.chc-chimes.com (jade.chc-chimes.com [216.28.46.6]) by hub.freebsd.org (Postfix) with ESMTP id F21DD37C253 for ; Mon, 14 Aug 2000 16:21:10 -0700 (PDT) (envelope-from billf@jade.chc-chimes.com) Received: by jade.chc-chimes.com (Postfix, from userid 1001) id C9A0E1C65; Mon, 14 Aug 2000 19:21:08 -0400 (EDT) Date: Mon, 14 Aug 2000 19:21:08 -0400 From: Bill Fumerola To: Bruce Petro Cc: hackers@FreeBSD.ORG Subject: Re: ipfw drop packets based on SYN &TTL Message-ID: <20000814192108.R65562@jade.chc-chimes.com> References: <383590598.966293068769.JavaMail.root@web303-mc.mail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <383590598.966293068769.JavaMail.root@web303-mc.mail.com>; from bpetro@usa.com on Mon, Aug 14, 2000 at 06:44:28PM -0400 X-Operating-System: FreeBSD 3.3-STABLE i386 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Mon, Aug 14, 2000 at 06:44:28PM -0400, Bruce Petro wrote: > Is this similar to the following kernel configuration? > options TCP_DROP_SYNFIN #drop TCP packets with SYN+FIN Not at all. The original poster is looking to drop all packets with a certain tcp syn#, where the TCP_DROP_SYNFIN option (and you must turn on the corresponding sysctl for it to be enabled) drops all packets with both the "syn" and "fin" flags set. functionally equivalent to: ipfw add drop tcp from any to any tcpflags syn,fin -- Bill Fumerola - Network Architect, BOFH / Chimes, Inc. billf@chimesnet.com / billf@FreeBSD.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message