[COLUG] virtual mailboxes: procmail vs maildrop

[Scott Merrill]

Rob Funk wrote:
> I based my setup on:
>   http://high5.net/howto/

Aye, I've been following this, too.

>>Postfix's virtual delivery agent doesn't easily allow me to pass
>>incoming messages to SpamAssassin, nor does it provide a very elegant
>>solution for vacation messages.  I know solutions exist for both of
>>these, but I'm hesitant to change too many variables at one time.
> 
> 
> For SpamAssassin, I find it cleanest (and best-documented) to use 
> postfix's content_filter directive to pass the message to 
> amavis/spamassassin, and from there pass it back to postfix.  This is the 
> way "Postfix: The Definitive Guide" suggests.

I haven't looked at this book yet, though I've heard good things about
it.  Can you share with me in what ways the content_filter directive is
better than passing the mail to procmail?

With the high5 virtual user set up, I would like to use per-user
SpamAssassin settnigs, stored in the database.  SquirrelMail has a nice
plugin for users to configure their options to taste.  Would these be
honored with postfix's content_filter mechanism?

> Postfix Admin allows users to setup vacation messages, though I've 
> disabled that feature and haven't tried it.
>   http://high5.net/postfixadmin/

I was turned off from their vacation implementation for several reasons:

1) the FILTER_README explicitly states that performance drops by several
factors when using this method.  I don't know how procmail impairs
performance, but I've never seen anything about it explicitly saying
"this slows your system down a lot".

2) the high5.net forums have a lot of discussion going toward a new
vacation script, written in perl.  I'd like to avoid perl's overhead, if
possible.

3) the high5.net virtual vacation setup allows users to define who else
ought to (also) receive their mail while they're on vacation.  I don't
want that.  I just want a simple auto-response.

4) I have a working vacation procmail recipe for local users.  I wanted
to adapt that for virtual users with as little modification as possible,
if possible.

>>So on a lark, using the maildrop filter lines from
>>/etc/postfix/master.cf, I made a procmail filter:
> 
> 
>>  procmail  unix  -       n       n       -       -       pipe
>>    flags=DRhu user=vmail argv=/usr/bin/procmail -a ${recipient}
> 
> 
> I think you want to change the -a to -d to specify local delivery (compare 
> the meanings of the two in the man page), but other than that it looks 
> fine to me.

Actually, I _do_ want the -a to be -a, so that the first command-line
argument to procmail is the email address to which this message was sent
(ie: my virtual user).  But it looks like I want "-d vmail" as well.
Thanks for the heads-up.

> You might also look into the mailbox_command setting for main.cf.

mailbox_command is for local accounts only, from what I've read.  Using
the high5.net template, virtual users won't be handled by
mailbox_command, will they?

With my procmail filter in master.cf, I use:
   virtual = procmail
to define which transport to use for virtual recipients.

Thanks for the response, Rob.

-- 
skippy at skippy.net | http://skippy.net/

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