ietf-mta-filters
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Re: comments? hashcash based MTA filtering

1999-02-24 09:11:13

I am requesting comments from this group because it seems the closest
match of IETF topic to "technical solutions to UBE".  I am open to
comments as to how best to progress this technical solution.

We are not trying to solve the spam problem.  That said, I like
hashcash.  Adding a test for a hashcash value is trivial.  But getting
Sieve out there is a large amount of work in itself.

Possibly a technical anti-spam group could be formed.  One of my
reasons for posting the request for comments was to get feed back on
the question of where hashcash should be progressed.

The originator is required to send with email a costly to compute
token bound to that resource name.  Example: Coyote emails Roadrunner,
he computes a hash collision on "roadrunner(_at_)birdseed(_dot_)org".  
birdseed.org
runs a MTA filter rejecting mail without hashcash postage.

The problem with this is that it means the amount of computational power 
that a mailing list costs is rather high.

You need some kind of free-reply tokens (say by subcribing to the
mailing list using an email address of special form), or allow list of
email addresses not requiring hashcash to get around problems like
this.

Adam