SUMMARY: Mail Filters

From: George Pallas (
Date: Fri May 07 1993 - 09:33:39 CDT

Last week I asked the list about filters for incoming mail. I received a
number of responses:

1. Use .forward files.

    Simple, yes, but I want the filtering to take place *BEFORE* delivery,
    not *AT* delivery, so the system manager controls it. (Note: Some of our
    mail from the Internet is forwarded to a non-UNIX office automation

2. Use a database to maintain user aliases and generate /etc/aliases files.

    Attractive, but I don't have a database handy yet. We may be getting one
    in the near future, though, so this may pan out later.

3. Use procmail for the local delivery agent.

    Procmail is the clear favorite (if we were voting). I looked at it and it
    is tremendously flexible. But unless I missed something, the filtering
    takes place at delivery and is under the user's control. This package
    looks so useful I may install it anyway, although it won't do exactly
    what I need in this case.

4. Use Elm, mailagent, or deliver.

    All three do their filtering at delivery and under user control. We do
    have Elm, and it's a pretty nifty package, but it won't filter the way
    I want it to.

5. Write a script to front-end sendmail.

    If I change anything, this will probably be the way I have to go, unless...

6. Use Zmailer.

    I just got this and it looks promising but I haven't got far enough into it
    to be sure.

7. One respondent pointed out that I mangled the Queen's English by using the
    non-existent word `edicted'.

8. At least two respondents suggested that I change the edict. Nice idea but
    not an option.

Thanks to all who responded:

Chris Siebenmann <>
Patrick O'Callaghan <>
Pete Hartman <>
Rick Dipper <>
Steve Hanson <> (Alek O. Komarnitsky) (Donald McLachlan) (David R. Linn)
hughes@FSL.ORST.EDU (l.e. hughes) (Paul Lord) (Ron.Madurski)
stern@sunne.East.Sun.COM (Hal Stern - NE Area Systems Engineer) (Lewis E. Wolfgang)

---------------------------- Original Query Below ----------------------------

> Greetings Fellow Sysadmins,
> Upper level management at my company has mandated that we have the ability
> to block mail from the Internet from reaching users who do not want it.
> The mechanism we use (which I inherited) to accomplish this is to use a
> separate system as a mail hub with its own "special" version of /etc/aliases.
> This scheme works and is very simple in concept. But the number of people
> who want to receive mail from the Internet has grown from a small handful
> to nearly 400 users, and the effort to keep this "simple" mechanism working
> is growing by leaps and bounds.
> What I need is a way to selectively filter mail before it gets injected
> into the delivery mechanism. A filter on outbound mail would be nice but
> it is inbound messages that are the main issue. Has anyone succeeded in
> doing something like this before? Is there any FTPable software that will
> either do the job or help do it?
> Thanks for any assistance you can provide.

George Pallas                              Voice:   614-764-6301
Manager, Systems Management Section        FAX:     614-761-5047
OCLC, Inc.                                 Email:
6565 Frantz Road                           "This time for SURE!"
Dublin, OH   43017                         -- Bullwinkle J. Moose

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