Date: Wed, 8 Dec 1999 11:36:43 -0000 From: Steven Fletcher <stevenf@shellnet.co.uk> To: <freebsd-net@freebsd.org> Subject: Very odd problem with email. Message-ID: <277A0E0FE38ED311A66A00A0C9D43A3D0781F5@data.shellnet.co.uk>
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Hi all; Wonder if anyone can advise here. We have been running sendmail/QPOP now for 3 years on FreeBSD-2.2.5 and have had no big problems untill now. Since the start of this month, a few of our customers have been having problems with their POP3 access - certain emails are just jamming dead. These don't containt any attachments, they're just plaintext emails. When I try to check the mail files over POP3, from certain hosts (shells in the US etc), I can get all the mail messages fine. However some of our customers dial other ISP's in the UK: Netcom UK, Virgin, some have leased lines - they are by no means busy though. From these accounts I can login over POP3, send "RETR 1", and the mail stops being sent at the same charachter, every time - it's 100% reproducible now on 3 UK ISP's trying to access our servers. However from machines based on JAnet (MCC) I am able to pull down the affected mail file with no problem, as I am also able to pull from various machines in the US with success. The same again works perfectly on our local network. 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. In the last 5 minutes though, I've noticed that the file can't be transferred over FTP either, failing at the same point for the given machines each time. Quick tests are also showing that the file won't work when transferring between an NT machine here and another NT machine at the same location as the test FreeBSD machine. Thus, in the time I've been writing this email, it certainly looks like the problem lies with our upstream provider (UUnet) - they've got 7 people working on it now - but I'm now wondering if anyone here has ever seen such a problem before - it looks like a very descreet problem to me indeed. If anyone can shed *any* light I'd be most appreciative, but could you please reply direct to myself also as I am not subscribed to -net at this address. Many thanks; Steven Fletcher stevenf@shellnet.co.uk To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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