From owner-freebsd-hackers Sat Sep 26 17:56:36 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id RAA14176 for freebsd-hackers-outgoing; Sat, 26 Sep 1998 17:56:36 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from cypher.net (zen.pratt.edu [205.232.115.155]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id RAA14154 for ; Sat, 26 Sep 1998 17:56:27 -0700 (PDT) (envelope-from black@cypher.net) Received: (qmail 27241 invoked by uid 512); 27 Sep 1998 00:46:30 -0000 Message-ID: <19980926204630.A20043@cypher.net> Date: Sat, 26 Sep 1998 20:46:30 -0400 From: Ben Black To: dg@root.com, Tony Jones Cc: hackers@FreeBSD.ORG Subject: Re: TCP (http) problem References: <199809270000.RAA00288@zebedee.local> <199809270033.RAA17588@implode.root.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.93.2i In-Reply-To: <199809270033.RAA17588@implode.root.com>; from David Greenman on Sat, Sep 26, 1998 at 05:33:40PM -0700 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG actually, this may be a bug in IIS4. i have seen a problem exactly as you describe (can't get to certain sites, those running IIS4, but everything else works fine) when the path MTU is not the same as the MTU on the IIS4 server's LAN. since the smaller MTU hop was under my control, i increased the MTU and everything worked. whether anyone upstream was blocking icmp messages used in path MTU discovery, i don't know. ben On Sat, Sep 26, 1998 at 05:33:40PM -0700, David Greenman had most eloquently written: > >Eventually the http connection will time out. > > > >I've upgraded -stable, the Linux version of Netscape to v4.06, tried my old > >BSD Netscape 3.0 all with the same results. The BSD Netscape _used_ to work > >fine, as did the Linux versions. > > > >I posted to -stable and someone suggested I disable TCP extensions (I'd already > >tried this) and also to try sending large ICMP packets (1472) to see if it was > >a fragmentation problem. The pings worked fine. > > It sounds like a problem with Path MTU Discovery. Your ISP is probably > blocking outbound "ICMP_UNREACH_NEEDFRAG" messages. You might try setting > a smaller MTU/MRU on your PPP connection (I suggest 552). > > -DG > > David Greenman > Co-founder/Principal Architect, The FreeBSD Project > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message