From owner-freebsd-net Wed Dec 8 6: 4:41 1999 Delivered-To: freebsd-net@freebsd.org Received: from zibbi.mikom.csir.co.za (zibbi.mikom.csir.co.za [146.64.24.58]) by hub.freebsd.org (Postfix) with ESMTP id 3E4F315514 for ; Wed, 8 Dec 1999 06:04:26 -0800 (PST) (envelope-from jhay@zibbi.mikom.csir.co.za) Received: (from jhay@localhost) by zibbi.mikom.csir.co.za (8.9.3/8.9.3) id QAA81133; Wed, 8 Dec 1999 16:03:51 +0200 (SAT) (envelope-from jhay) From: John Hay Message-Id: <199912081403.QAA81133@zibbi.mikom.csir.co.za> Subject: Re: Very odd problem with email. In-Reply-To: <277A0E0FE38ED311A66A00A0C9D43A3D0781F5@data.shellnet.co.uk> from Steven Fletcher at "Dec 8, 1999 11:36:43 am" To: stevenf@shellnet.co.uk (Steven Fletcher) Date: Wed, 8 Dec 1999 16:03:51 +0200 (SAT) Cc: freebsd-net@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL54 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > > I have now tried what I consider to be 'everything' - swapping the > mailserver hardware, swapping the POP3 server that we use (tried QPOP & > Cucipop - QPOP emails are getting slightly further than those delivered via > Cucipop). Running tcpdump on both the affected machines (the mailserver & > the external machine) shows that ACK's don't seem to be getting through: > > 16:42:31.530365 194.129.209.11.pop3 > www5.shellnet.co.uk.4969: P > 1590:2928(1338) ack 35 win 17520 (DF) > > Is repeated at increasing intervals after the file stops. One possibility is that the path mtu discovery is getting screwed up somewhere. That may happen if some link have a smaller mtu that your local net and icmp NEEDFRAG packets are blocked. John -- John Hay -- John.Hay@mikom.csir.co.za To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message