MTA preferences for use with MailScanner

[Eric Dantan Rzewnicki]

On Wed, Aug 04, 2004 at 03:28:34PM -0300, Mariano Absatz wrote:
> On Tue, 3 Aug 2004 18:46:39 -0400, Eric Dantan Rzewnicki
> <rzewnickie at rfa.org> wrote:
> > On Thu, Jul 29, 2004 at 08:38:57AM -0300, Mariano Absatz wrote:
> > > I heard, from knowledgable people, that both Postfix and Exim are
> > > nice, easy to configure and have good documentation and mailing list
> > > support... the only thing that I disliked was when Julian said that
> > > the queue format of Postfix is binary and not plain ASCII... this
> > > scares me a lot since, in a crisis, you aren't able to use your
> > > average set of text tools to resolve it...
> > Is this really true? I know postfix queuefiles don't have linebreaks in
> > them, but does that make them binary?
> > Anyway, postfix comes with the postcat utility which takes a queuefile
> > and prints it to standard out nicely formatted with line breaks. So, you
> > can do whatever standard text manipulations on it you desire. The
> > postdrop utility is also useful for dealing with queuefiles.
> There's more to mail queue files than the message itself... you
> usually have the envelope, maybe including status info... I guess the
> utility you name doesn't nicely print them... nor is there a utility
> to reverse the process (or is it?).

I'm not sure about reversing the process ... but, the output of postcat
does include the envelope information, I think. (appologies if I'm wrong
on that)

> Since MailScanner _needs_ the envelope info and has to rebuild it when
> it finishes, it has no other route than mess with the binary files...
> As to the 'standard' way of interacting with Postfix, I don't know,
> but I suspect it is something similar to milter, that gets called for
> every message...

amavis uses postfix's content filter which, as you said, can only do a
single message at a time iiuc.

> The beauty and speed of MailScanner comes from the fact that it
> batches quite a few messages ans processes all of them together,
> invoking the virus scanner for all the attachments of all the messages
> in one sweep thus saving loads of 'system' invocations for this...

and that's one of many reasons I'm using MailScanner instead of amavis,
even though postfix's author doesn't approve.

> Maybe I'm too used to zmailer, which uses the same model MailScanner
> does (process interaction is mostly performed via the filesystem), but
> I love it... if something's going wrong in some place I can stop only
> one piece and let the rest keep working while I repair it...

I'm still using 2 postfix instances with MailScanner for the same
reason (well, in addition the hold queue not being available in the old
postfix version included in debian stable). I can start and stop postfix
incoming and outgoing separately from each other and from mailscanner.

-Eric Rz.

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