From owner-freebsd-questions@FreeBSD.ORG Wed Jul 11 13:08:57 2007 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id B699916A41F for ; Wed, 11 Jul 2007 13:08:57 +0000 (UTC) (envelope-from wundram@beenic.net) Received: from mail.beenic.net (mail.beenic.net [83.246.72.40]) by mx1.freebsd.org (Postfix) with ESMTP id 7BB0213C483 for ; Wed, 11 Jul 2007 13:08:57 +0000 (UTC) (envelope-from wundram@beenic.net) Received: from [192.168.1.34] (a89-182-90-164.net-htp.de [89.182.90.164]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.beenic.net (Postfix) with ESMTP id EBAC8A44529 for ; Wed, 11 Jul 2007 14:39:29 +0200 (CEST) From: "Heiko Wundram (Beenic)" Organization: Beenic Networks GmbH To: freebsd-questions@freebsd.org Date: Wed, 11 Jul 2007 14:40:47 +0200 User-Agent: KMail/1.9.7 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Message-Id: <200707111440.47637.wundram@beenic.net> Subject: Re: Some hosting weirdness... X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 11 Jul 2007 13:08:57 -0000 On Wednesday 11 July 2007 14:19:09 Eric F Crist wrote: > > What should I look for? Is there possibly some weird caching issues > at their ISPs? How can I fix this? Do a tcpdump when someone connects from their network and check for TCP-MSS= =20 issues, which would be my first guess when small files/items load fine over= =20 HTTP but items larger than a single TCP-packet won't (which basically fits= =20 the symptoms you describe). As some ISPs will do IP fragmentation when a packet too large to fit over t= he=20 downlink to a customer arrives, you'll not see this problem with these. Tho= se=20 ISPs that don't do IP fragmentation on the downlink (quite a few) generally= =20 should send out an ICMP-message with a "Fragmentation needed" error (which= =20 appears in the tcpdump), but some don't do that either. Generally, the MSS in their SYN-packet when connecting to your webserver=20 should be below 1460; most probably at 1452 (which is DSL and cable AFAIK),= =20 or more generally speaking (their) MTU-40, and the _IP_ packet size your ho= st=20 sends back should always be equal to or below the minimum of your MSS (whic= h=20 is sent in the SYN/ACK packet) and their MSS, plus 40. If this is not the=20 case, you have an issue. =2D-=20 Heiko Wundram Product & Application Development =2D------------------------------------ Office Germany - EXPO PARK HANNOVER =20 Beenic Networks GmbH Mail=E4nder Stra=DFe 2 30539 Hannover =20 =46on +49 511 / 590 935 - 15 =46ax +49 511 / 590 935 - 29 Mail wundram@beenic.net Beenic Networks GmbH =2D------------------------------------ Sitz der Gesellschaft: Hannover Gesch=E4ftsf=FChrer: Jorge Delgado Registernummer: HRB 61869 Registergericht: Amtsgericht Hannover