From owner-freebsd-isp Tue Nov 17 17:17:06 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id RAA26708 for freebsd-isp-outgoing; Tue, 17 Nov 1998 17:17:06 -0800 (PST) (envelope-from owner-freebsd-isp@FreeBSD.ORG) Received: from root.com (root.com [198.145.90.17]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id RAA26700 for ; Tue, 17 Nov 1998 17:17:01 -0800 (PST) (envelope-from root@root.com) Received: from root.com (localhost [127.0.0.1]) by root.com (8.8.8/8.8.5) with ESMTP id RAA02290; Tue, 17 Nov 1998 17:17:54 -0800 (PST) Message-Id: <199811180117.RAA02290@root.com> To: Barrett Richardson cc: John Heyer , FreeBSD-isp@FreeBSD.ORG Subject: Re: Just Plain Weird problem In-reply-to: Your message of "Tue, 17 Nov 1998 19:15:27 EST." From: David Greenman Reply-To: dg@root.com Date: Tue, 17 Nov 1998 17:17:54 -0800 Sender: owner-freebsd-isp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org >Try hitting sites that you know are running FreeBSD (www.freebsd.org, >ftp to ftp.cdrom.com, www.best.com, www.aye.net, www.etinc.com). I had >a similar problem with a WAN card in 2.2.5, connections to other >FreeBSD boxes worked flawlessly, connections to micros**t boxes, >peering with other routers would hang, but packets would route ok. >Try turning off tcp_extensions in rc.conf, it didn't help me. >With some tests I ran on mine, the problem was somewhat data dependant. >I could put a text file with a bunch of a's in it in on an sgi box, >and it would work ok. I could grab a file with random data in it, >and it would hang. Could duplicate the same behaviour with kermit >over tcp with ridiculously small packets (90 bytes). > >Something I never did was watch the ACKs with tcpdump to see if something >was different there with good connections vs. bad connections. In my experiance, this is usually caused by an overly restrictive firewall setup that blocks all ICMP and thus breaks Path MTU Discovery. Next time, try changing your default route, adding "-lock -mtu 1500". This will disable PMTU Discovery. NOTE: You'll need FreeBSD 2.2.6 or later for this to work. -DG David Greenman Co-founder/Principal Architect, The FreeBSD Project To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message