From owner-freebsd-net@FreeBSD.ORG Tue Dec 30 06:34:43 2003 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9F01F16A4CE for ; Tue, 30 Dec 2003 06:34:43 -0800 (PST) Received: from mail.icomag.de (ns.icomag.de [195.227.115.162]) by mx1.FreeBSD.org (Postfix) with ESMTP id DE85643D45 for ; Tue, 30 Dec 2003 06:34:41 -0800 (PST) (envelope-from bgd@icomag.de) Received: from localhost (localhost [127.0.0.1]) by mail.icomag.de (Postfix) with ESMTP id D3E1122E32 for ; Tue, 30 Dec 2003 15:34:39 +0100 (CET) Received: by mail.icomag.de (Postfix, from userid 1019) id 8B1FA22E36; Tue, 30 Dec 2003 15:34:36 +0100 (CET) Date: Tue, 30 Dec 2003 15:34:36 +0100 From: Bogdan TARU To: freebsd-net@freebsd.org Message-ID: <20031230143436.GB27308@icomag.de> Mail-Followup-To: freebsd-net@freebsd.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.1i X-Virus-Scanned: by AMaViS Subject: strange ICMP problems X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Dec 2003 14:34:43 -0000 Hi, I've got some strange ICMP problems on my FreeBSD router/firewall. I'm trying to ping a host (dst) from this router, and I don't get any answer (100% packet loss). A tcpdump shows me (src=freebsd router/firewall, dst=destination host of the ping): src > dst: icmp: echo request (ttl 64, id 15739, len 84) dst > src: icmp: echo reply (ttl 58, id 33870, len 84) src > dst: icmp: time exceeded in-transit for dst > src: icmp: echo reply [ttl 1] (id 33870, len 84) [tos 0xc0] (ttl 254, id 6572, len 56) over and over and over again. This happens only with ICMP and only for this destination HOST! (It doesn't happen if I try from a different source box, though). I guess it's the freebsd router's fault, because it definitely receives a packet with ttl 58, and sends an ttl exceeded. The router is running freebsd 4.8-RELEASE, with IPF v3.4.31, and IPnat for natting. It's been running ok for about 100 days, and the problems with this destination hosts appeared suddenly, without configuration changes on any end. Any hints if IPF is really the problem? Thanks, bogdan