Filtering on List-Id (was Re: Administrivia: Subject line tagging)

[Tom Buskey]

There's another way to prevent two replies.  Use an invalid email address.
 I wonder wh you even bother with this procmail rule as you're never going
to get private replies from your postings on the list.....

> On Sun, Apr 18, 2004 at 09:11:09PM -0400, bscott at ntisys.com wrote:
>>   But anyway, the "List-Id" header is guaranteed to be present and the
>> same
>> for all messages delivered through this mailing list.  So, one should
>> filter on that, and not anything else, to identify list mail.
>
> This is a point worth taking note of.  Filtering ONLY on list-id  can
> fail.  Often, a poster replies to both the list, and the original
> poster.  In this case, the OP will normally receive two copies of the
> message: one from the list management software (with the expected
> List-Id header), and one which comes directly from the sender (which
> will NOT have the List-Id header).
>
> If you DON'T  use procmail (or something else) to filter duplicate
> messages, you'll get two copies of the message.  One will be
> "properly" filtered, and the other will not.  If you DO use procmail to
> filter duplicates, you will only receive one copy of the message. You
> probably will first receive the message which comes directly from the
> sender, and thus it will not be filtered properly.
>
> This is the rule I use to filter all mail from the GNHLUG and BLU
> mailing lists into my "Linux" folder.  It's not 100% perfect, but it
> fails (with false positives) only in extremely rare cases.
>
>   :0
>   * (gnhlug|discuss).*@.*(gnhlug|blu)
>   folders/Linux
>
> This matches on any header, any occurrence of the following:
>
>   gnhlug-discuss at mail.gnhlug.org
>   discuss at gnhlug.org
>   discuss at blu.org
>
> ...as well as a number of patters which are not official list
> addresses for either list, but which are very unlikely to occur
> anywhere else.
>
> Of course, if you're filtering only for gnhlug, you could pretty much
> eliminate false positives with this:
>
>   * gnhlug-discuss at mail\.gnhlug\.org|discuss at gnhlug\.org
>
> I will also note for the record that the List-ID header for this list
> appears to have a small error...  I think there's a '.' where the '@'
> should be.  It may not be crucial, but if people expect to match on
> 'gnhlug-discuss at mail.gnhlug.org', it will fail.
>
> --
> Derek D. Martin    http://www.pizzashack.org/   GPG Key ID: 0xDFBEAD02
> -=-=-=-=-
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