Re: Is predictable spam filtering a vulnerability? (silently drop ping messages)

[Stephen Warren <swarren () wwwdotorg org>]

David Brodbeck wrote:

> As for rejecting invalid bounces, some people have been experimenting with
> adding a short crypto hash to the envelope sender address of each message.
> If a bounce comes in and the hash is wrong, it has to be invalid, so it's
> rejected.  Google for 'signed envelope sender' for more info.  This is an
> interesting idea because it doesn't require anyone else to do anything --
> you can implement it on your own domain and see immediate benefits.
>  
TMDA (http://www.tmda.net/) is a system that'll allow you to do this.

Yes, whilst TMDA is a challenge-response system which some won't like, 
you can (trivially) configure it not to ever challenge, and use it for 
other means, such as validating crypto-style envelope senders.

--
Stephen Warren, Software Engineer, Parama Networks, San Jose, CA
swarren () wwwdotorg org                  http://www.wwwdotorg.org/