[Mimedefang] sendmail as mail proxy

[Tim Kramer]

Well, you hit it on the head with the older BSDi.  The threaded milter
was spitting up misc. errors, mostly related to disk I/O (if I remember
correctly).

With FreeBSD, the problem had something to do with the interaction
between the virus scanner and MD.  Above a certain load, the virus
scanner started to fail.  I doubt it had anything to do with MD.

With Linux, it was the system load.  The system would drop to 0% idle
and stay there for longer and longer periods of time.  Occasionally, a
connection would "stick" open. (It probably had timed out on the far
end.)  This gradually ate up memory.

The constraint that I have to work with is the selection of virus
scanners.  I'm only allowed to use two commercial scanners and one of
them doesn't have a command-line version.  The usable OS's depend on if
there's a version of that scanner available.  In this case, it's
FreeBSD, Linux, or platforms capable of emulating Linux, like BSDi
(which we already own licenses to).

Load testing returned the following:

	BSDi	80-90% idle
	Linux	0-10% idle (mostly 0%)
	FreeBSD	20-30% idle

Because I had originally wanted to get out of the spam-filter cleaning
business, I modified out existing scripts to single-task scan for
viruses and score for spam.  It works well, but without all of the bells
and whistles of MD.  My personal shortcoming is I don't yet understand
the hooks that Milter makes available.

- Tim




On Mon, 2002-07-08 at 20:15, David F. Skoll wrote:

> 
> Could you elaborate?  Was the technical obstacle related to the OS,
> to MIMEDefang or to the virus scanner?

> 
> Older BSDi's have rotten pthreads support, which is why milter doesn't
> work too well.
>