[hashcash] Re: Hashcash in Exim

Forwarding a mail from Paul Schmidt which didnt make it for some
reason (received in admin bounce message).

To: hashcash@xxxxxxxxxxxxx
From:  Paul Schmidt <paul@xxxxxxxxxxxxxx>
Subject: [hashcash] Re: Hashcash in Exim
Date:  Mon, 10 Sep 2007 16:19:15 -0400

eric,

Thanks for the response.

I think that it can be done server wide by adding the following:

        remote_smtp:
        driver = smtp
        headers_add = ....

My current implementation would be to have the added header by generated 
by some perl code that would return the hashcash header or nothing, if
no header should be inserted.  The code to generate the header could use 
different rules for generation to keep the number of generations down, 
or do a database lookup for pre-generated hashcash headers.

If this doesn't seem like a workable approach, let me know.  Email and 
Exim are not my field of expertise.

By the way, the code for the implementation seems like it would be much 
like the CAMRAM code.  camram.org is not working.  Has that project ceased?

--

Paul

Eric S. Johansson wrote:
> Paul Schmidt wrote:
>> Is there a way to generate Hashcash in Exim in the background?  I want 
>> to do this for a single domain on our dedicated server, not all domains.
> 
> sadly there may be none.  you need an mta that lets you distinguish 
> between inbound and outbound traffic.  I've faked it with postfix by 
> using content or stamping filters on different port/address mappings (2 
> ip addresses:25 or 1 ip and ports 25/587.  when I last looked at exim, 
> it only had a simple filter infrastructure suitable for inbound 
> filtering only.  has this changed?
> 
> --- eric
>

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