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Not keeping state Was: What DB-Backed forwarding is.

2004-12-08 16:22:09
On Wed, Dec 08, 2004 at 02:39:55PM -0500, Meng Weng Wong wrote:

smaller sites can do DB fine.

larger sites would prefer not to keep state.

Can we please discuss my proposed alternative forwarding?

I think it covers some of the objections seen, other objections could
probably also be dealt with (except David's "the world needs to change")

Basic outline, which can be beautified:


At forwarder's site:

1: mail enters the system and is delivered to the user
2: the user uses (for instance) procmail to:
  2a) sign the message or encrypt it
  2b) resend the message as an attachment

At final recipient's site:

3: verify the origin (is it really a forwarder; the user knows)
4: verify the message (does the user recognize its own signature)
5: loose the wrapper, deliver the message

Incoming mail on forwarder's site, as a bounce:

3: verify the signature and recognize the message as a legitimate bounce
4: unwrap, submit as bounce to the originator's site


- The forwarded message is MAIL FROM the forwarder's site, SPF success.
- Bounces are returned.
- Can be done inside a MUA, independent of MTA technology if desired
- User controlled if desired, site controlled if desired
- The final destination is kept a secret to the originator of the message,
  even when the message results in a bounce
- Information is in the message itself, no need for databases, return
  path rewriting etc.

Forwarding messages as an attachment can't be a problem, spamassassin
seems to work just fine with it.  Automating this should also not be
a problem.  

cheers,
Alex


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