From owner-freebsd-questions@FreeBSD.ORG Mon Mar 1 15:15:42 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 089DA16A4CE for ; Mon, 1 Mar 2004 15:15:42 -0800 (PST) Received: from spock.ste-land.com (spock.ste-land.com [64.32.179.40]) by mx1.FreeBSD.org (Postfix) with ESMTP id C8D2043D2F for ; Mon, 1 Mar 2004 15:15:39 -0800 (PST) (envelope-from ste@ste-land.com) Received: from ste-land.com (bgp377940bgs.plnfld01.nj.comcast.net [68.36.5.198]) by spock.ste-land.com (Postfix) with ESMTP id C7D742D24C; Mon, 1 Mar 2004 18:15:38 -0500 (EST) Message-ID: <4043C41A.4010706@ste-land.com> Date: Mon, 01 Mar 2004 18:15:38 -0500 From: "Shaun T. Erickson" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4b) Gecko/20030507 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Remko Lodder References: <20040301230559.4218D2B4DA4@mail.evilcoder.org> In-Reply-To: <20040301230559.4218D2B4DA4@mail.evilcoder.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: freebsd-questions@freebsd.org Subject: Re: ipfilter tcp flags question X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 Mar 2004 23:15:42 -0000 Remko Lodder wrote: > i do it like this: > > block in log quick proto tcp all flags FUP > block in log quick proto tcp all flags SAFRU/SAFRU > block in log quick proto tcp all flags SF/SF > block in log quick proto tcp all flags SR/SR I'll have to scratch my head over that one for a bit, before I understand it, but I guess you're saying that the above 4 rules imply a fifth in that if none were set, it couldn't get through them, right? I really dislike implied rules, and avoid them if at all possible, as they are hard to maintain. :) Is there no way to explicitly test for no flags being set? -ste