Re: [Gnu-arch-users] Re: Describing archives (new feature at the mirror)

[Andrew Suffield]

On Sat, Apr 03, 2004 at 12:45:14AM +0100, Julian T J Midgley wrote:
> On Fri, 2 Apr 2004, Andrew Suffield wrote:
> 
> >
> > The only sane place where it can be fixed is at the sender
> > end. Removal of duplicates without opening trivial DoS attacks against
> > your mailbox is impossible.
> 
> This is arrant nonsense.

Right back at you.

> > By the time the duplicate mails reach the destination, they have been
> > significantly munged by the MLM; this list runs on mailman, which is
> > spectacularly bad in this respect. Now which one are you supposed to
> > deliver?
> 
> Erm, unless your MLM is spectacularly appalling (and mailman isn't (nor is
> any MLM that runs any list I've ever been subscribed to)) it won't alter
> the Message-Id header, which was, after all, designed to be unique per
> message.

You are assuming that the transformation an MLM performs on the mail
is completely without value, and you would never care which version
you receive. The problem with that idea should be obvious.

> So keep a cache of message-ids you've already seen, and throw
> any duplicates (arranging for your filters to drop the first copy of each
> mail into your inbox or mailing list boxes as you prefer).

And now anybody who can predict msgids, which frankly is not all that
hard (they are not designed to be secure) can selectively filter your
mail by forwarding you spam with suitable forged msgids.

-- 
  .''`.  ** Debian GNU/Linux ** | Andrew Suffield
 : :' :  http://www.debian.org/ |
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