Valid Message-Id: tagged as bad?

[Russ Allbery]

Christopher P Lindsey <isc.org at spamfodder.com> writes:

> With that in mind, is there a recommended pre-processor that can be used
> to wrap the mailing list/Web interface with the same types of checks?
> Yes, I can pull the code from the inn source and write a C binary to do
> it, but I would actually prefer a snippet of Perl code.  Yes, I can
> write one myself, but if there's one already out there...

Here's what I use:

    # Check the mail message ID and see if it looks reasonable.  If not,
    # rename it so that we'll generate our own.  Note that news servers may
    # reject message IDs with a trailing period, so don't allow them.  This
    # is not a complete check; a complete check should really use the code
    # from INN and needs more than a simple regex.
    my $id = $article->header ('message-id');
    $article->rename_header ('message-id', 'x-original-message-id', 'add')
        if ($id && $id !~ /^<[^\s\@>]+\@[^\s.>]+(\.[^.\s>]+)+>$/);

It seems to work pretty well.

> Also, is there any problem with me replacing bad Message-Ids with a
> properly generated one?  All messages will come from authenticated
> sources, so I'm not concerned about spam.  I just need to make sure that
> anything that comes through from any of the three input sources gets
> sent to all output media.

It can break threading, but other than that, no.

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>