Date: Fri, 25 Feb 2005 17:58:40 +0100 From: Oliver Brandmueller <ob@e-Gitt.NET> To: freebsd-isp@freebsd.org Subject: Re: SpamAssassian with FreeBSD and Big Mail Server Message-ID: <20050225165840.GC70464@e-Gitt.NET> In-Reply-To: <421C65CA.9060606@adamstudios.com> References: <20050223110037.177AB43D2F@mx1.FreeBSD.org> <421C65CA.9060606@adamstudios.com>
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[-- Attachment #1 --] Hi. On Wed, Feb 23, 2005 at 12:15:22PM +0100, Randy Adamczyk wrote: > do you receive a _lot_ of spam? if you are running into recource > problems because of spam, you should look into greylisting: > > http://www.greylisting.org/ > http://projects.puremagic.com/greylisting/whitepaper.html > > greylisting for exim + spamassassin: > http://greylisting.org/implementations/sa-exim.shtml > > i use greylisting with postfix, spamassassin and virus-scanners with > amavis-new. spamassassin hardly has any work to do since i implemented > greylisting. And when doing things greylisting, please try to see both sides. Since people tend to see only their side, I will now describe the medium-sized-ISP side of things. Well, everyday life. Spam of course also hit's our servers and due to legal things we cannot just filter every incoming mail. Queues are around 5000 mails. That's OK with our hardware. Then, one day, someone invented greylisting. Great idea. Since especially universities and other organizations like this have adopted it, his means that quite a lot of mails go to servers with greylisting. Queues have grown since then. 10000 per server average is what we see now. The problem here is, that in theory the server tries again after 5 minutes and gets the mail delivered. The real side of the problem is: The bigger the queues are, the more time it takes until you come up with the same mail again. So mail takes not 30 seconds to arrive,not 5 minutes like greylisting theory, but maybe half an hour. That's already a value some customers complain about. Now people without the slightest idea what they are doing start to implement greylisting. They get the connection from 123.123.123.1 the first time and send their temporary error. Fine. The queue runner on 123.123.123.7 picks up the mail next time. Temporary error, because the .1 is currently allowed to send the mail. OK, second temporary error. Mail stored in lower prio, next delivery attempt in one hour. And so on. Greylisting makes a lot of trouble at big sites. And mens longer and sometimes very delivery times for mail. Great idea, yeah, spread that to the world, maybe the day will come, when snailmail is faster... - Oliver -- | Oliver Brandmueller | Offenbacher Str. 1 | Germany D-14197 Berlin | | Fon +49-172-3130856 | Fax +49-172-3145027 | WWW: http://the.addict.de/ | | Ich bin das Internet. Sowahr ich Gott helfe. | | Eine gewerbliche Nutzung aller enthaltenen Adressen ist nicht gestattet! | [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (FreeBSD) iD8DBQFCH1lAiqtMdzjafykRAtxUAJ0cmzTWBuVb4ulGB0+3/I3Za+lpGgCfW0GH ihxiCeIG5Sbr9yG0KlnNruU= =HVQ/ -----END PGP SIGNATURE-----help
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