From owner-freebsd-hackers Sat Sep 26 20:22:50 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id UAA01598 for freebsd-hackers-outgoing; Sat, 26 Sep 1998 20:22:50 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from redfish.go2net.com (redfish.go2net.com [207.178.55.5]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id UAA01589 for ; Sat, 26 Sep 1998 20:22:48 -0700 (PDT) (envelope-from marcs@go2net.com) Received: from marcs by redfish.go2net.com with smtp (Exim 1.82 #2) id 0zN7No-0001fk-00; Sat, 26 Sep 1998 20:20:24 -0700 Date: Sat, 26 Sep 1998 20:20:24 -0700 (PDT) From: Marc Slemko X-Sender: marcs@redfish To: Ben Black cc: Tony Jones , hackers@FreeBSD.ORG Subject: Re: TCP (http) problem In-Reply-To: <19980926204630.A20043@cypher.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sat, 26 Sep 1998, Ben Black wrote: > 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. Doubtful, it is probably just a filtering thing. > > 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). More likely a site upstream; www.wellsfargo.com is blocking pings, so they may well be blocking other ICMP. That is their problem. http://www.worldgate.com/~marcs/mtu/ for a description of the likely problem and possible solutions. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message