From: Michael Orlitzky <michael@orlitzky.com>
To: gentoo-user@lists.gentoo.org
Subject: Re: [gentoo-user] clamav and spamassassin
Date: Sat, 03 Dec 2011 22:06:25 -0500 [thread overview]
Message-ID: <4EDAE3B1.8050808@orlitzky.com> (raw)
In-Reply-To: <CAA2qdGXj_-Ci_oZ9MWROhRAqcOo4K=gyF+8+b+=vahRGmFka=w@mail.gmail.com>
On 12/03/2011 09:48 PM, Pandu Poluan wrote:
>
>
> Thanks! Very helpful resources.
>
> You mentioned amavisd-new. What's their relationship? I mean, if I
> deploy postscreen, how will it affect amavisd-new?
>
Postscreen sits in front of smtpd, and handles all incoming connections.
It hands the "good" connections off to the real smtpd daemon.
Amavisd-new (in both before/after-queue configurations) interacts with
the real smtpd, so postscreen doesn't directly affect it at all.
What was I talking about?
With amavisd-new, a before-queue filter is generally nicer, because you
can reject spam, notifying the sender, rather than discarding it or
backscattering. But, amavisd-new is a hog, and with a before-queue
filter, an amavis process gets used every time ANY connection is made.
Since 95% of your connections will be crap (that is a technical term),
you waste tons of resources creating/killing amavisd-new processes for
botnets and other scum that will be rejected quickly.
On a busy server, it will kill you.
Postscreen only passes the "good" connections to a real smtpd, so with
postscreen running, new amavis processes only get used for those good
connections. If postscreen can get reject 90% of the incoming
connections, you'll use an order of magnitude less resources doing
before-queue filtering than you would without postscreen.
So, in essence, postscreen is what allows you to run the before-queue
filter with comparable resources to the after-queue filter.
next prev parent reply other threads:[~2011-12-04 3:08 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-03 19:52 [gentoo-user] clamav and spamassassin Grant
2011-12-03 22:54 ` Michael Orlitzky
2011-12-04 0:59 ` Grant
2011-12-04 1:35 ` Michael Orlitzky
2011-12-04 1:57 ` Grant
2011-12-04 2:10 ` Michael Orlitzky
2011-12-04 1:59 ` Pandu Poluan
2011-12-04 2:17 ` Michael Orlitzky
2011-12-04 2:48 ` Pandu Poluan
2011-12-04 3:06 ` Michael Orlitzky [this message]
2011-12-04 8:27 ` Pandu Poluan
2011-12-06 0:15 ` Grant
2011-12-06 0:45 ` Pandu Poluan
2011-12-06 0:52 ` Michael Orlitzky
2011-12-06 1:01 ` Pandu Poluan
2011-12-06 1:14 ` Michael Orlitzky
2011-12-06 3:24 ` Grant
2011-12-06 4:43 ` Michael Orlitzky
2011-12-06 16:32 ` Grant
2011-12-06 17:11 ` Michael Orlitzky
2011-12-06 19:17 ` Paul Hartman
2011-12-07 0:16 ` Pandu Poluan
2011-12-06 21:34 ` Grant
2011-12-06 22:20 ` Michael Orlitzky
2011-12-07 1:02 ` Grant
2011-12-07 16:38 ` Michael Orlitzky
2011-12-07 18:16 ` Grant
2011-12-07 18:56 ` Michael Orlitzky
2011-12-07 19:00 ` Michael Orlitzky
2011-12-08 0:49 ` Grant
2011-12-07 9:15 ` Pandu Poluan
2011-12-07 16:01 ` Grant
2011-12-07 16:47 ` Pandu Poluan
2011-12-07 0:57 ` Grant
2011-12-07 1:11 ` Pandu Poluan
2011-12-07 16:34 ` Michael Orlitzky
2011-12-07 18:08 ` Grant
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