Date: Tue, 20 Feb 2001 00:32:53 -0800 From: "Ted Mittelstaedt" <tedm@toybox.placo.com> To: "Nathan Vidican" <webmaster@wmptl.com>, <questions@FreeBSD.ORG>, <isp@FreeBSD.ORG> Subject: RE: Sendmail gone crazy, proliferating emails Message-ID: <00f501c09b17$b7b7c100$1401a8c0@tedm.placo.com> In-Reply-To: <3A9137F0.C177D65F@wmptl.com>
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Hi Nathan, I can't tell you WHY it happened, but I CAN tell you WHAT happened. First of all, it wasn't Sendmail that duplicated the mail, it was cucipop. I'll illustrate this step by step 1) message recieved by sendmail, written to user mailbox. 2) cucipop gets a "check mail" request from a pop client 3) cucipop moves the user mailbox file to a temp file to work on 4) cucipop transmits the message to the pop client 5) client successfully recieves the pop message and sends a delete command back to cucipop 6) cucipop attempts to delete the message, is unable to do so, spits out an error message 7) cucipop moves the temp file which still contains the message that was supposed to be deleted, back to the user mailbox, then exits. 8) User mailbox is now in exactly the same state as it was in before step #2 and after step #1 9) step #2 is repeated 10) step #3 is repeated 11) step #4 is repeated - now a second copy of the message has been transmitted to the client 12) step #5 is repeated 13) step#6 is repeated. and so on and so on, for ever and ever, each time the mail client gets another duplicate of the mail message. I could speculate that the mailserver ran out of lock resources for some reason, perhaps recompiling with MAXUSERS set higher would help. Ted Mittelstaedt tedm@toybox.placo.com Author of: The FreeBSD Corporate Networker's Guide Book website: http://www.freebsd-corp-net-guide.com > -----Original Message----- > From: owner-freebsd-questions@FreeBSD.ORG > [mailto:owner-freebsd-questions@FreeBSD.ORG]On Behalf Of Nathan Vidican > Sent: Monday, February 19, 2001 7:13 AM > To: questions@FreeBSD.ORG; isp@FreeBSD.ORG > Subject: Sendmail gone crazy, proliferating emails > > > Here's something interesting for you... > > I Came into the office this morning, and found that sendmail had been > duplicating incoming messages all night. I myself only found a few > emails which had duplicate receivals, eg two messages same time, same > sender, same content, same headers. I didn't think it was that big of a > deal, until my boss calls to say some other people within the office are > getting 100-200 copies of an email message. > First thing I did was turn of sendmail, and cucipop. Then I skimmed > the maillog, messages, and apache access logs (we're running a hacked-up > version of Neomail for a web-based client; seldom-used). I didn't find > anything out of the ordinary, no duplicate messages or anything. I did > note the receive log in maillog had a singular log for some of the > messages I was receiving several copies of. > The only error message, (logged both to the screen, and to > /etc/messages), was (several times for every user that had left outlook > running over the weekend checking their email): > > Feb 19 09:04:25 home cucipop[43229]: Error locking userX's mailbox > Feb 19 09:05:08 home cucipop[43236]: Error locking userY's mailbox > Feb 19 09:06:26 home cucipop[43244]: Error locking userZ's mailbox > > The machine had been running now for 70days since the last reboot, > (which was due to a power-failure, at which time the machine had been up > for a similar amount of time before with no real problems). So I don't > think it's a configuration problem, or else it probably would have been > note before now. Also, nothing was changed on the machine for some time > now; only two people have telnet/ssh access to the machine, and my boss > sure as heck didn't do it, on purpose or otherwise. > I then started to throw blame at MS Outlook, (using Outlook 2000 as > the client software on our LAN). I figured maybe someone got a stupid > little VB script which was pulling the addressbook from every internal > machine and bouncing around a few hundred emails all of\ver the place or > something. This wouldn't be so though, because a-sendmail would therefor > have a log of each individual message being sent from outlook to > wherever, and b-there were messages sent from the mail-server itself, > (eg periodic daily runs via cron), which I received three or four copies > of each, and I use netscape not Outlook for email personally. > Seeing nothing else unusual, and having no clue what if anything was > actually wrong, I started sendmail and cucipop back up. It has, (knock > on wood), not had any such problems since. I still need an explanation > of some sort though? What exactly happened and why? Has anyone else > every seen something like this before? What caused it? Could it just be > some sort of crazy fluke? > Desperatly trying to make some sense of this here... if anyone out > there has any ieas, questions, comments, concerns, or otherwise PLEASE > feel free to contact me. I would like to get this resolved, or at least > build an understanding as to why or how this happened in the firstplace. > > Nathan Vidican > webmaster@wmptl.com > Windsor Match Plate & Tool Ltd. > http://home.wmptl.com/ > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message
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