On Wed, 6 Jul 2005, David Woodhouse wrote:
> Some are advocating that the entire world should change -- all those
> hosting providers and other hosts which forward mail (including every
> *nix box with .forward files) should all be changed to mangle the mail
> as it passes through, so it gets a new reverse-path with a domain which
> is local to the forwarder, and then bounces to that generated
> reverse-path should be 'unwrapped' and sent back to the original sender
> of the original mail.
Thereby providing a nice means of subverting the forwarding host so that
it becomes a relay for junk, forcing you do adopt cryptographic
anti-forgery measures (none of which are fully designed/understood/
widely used yet).
Back in the 1980s people used "source routed" email with addresses like
this:
@a.domain,@b.domain:user@???
The syntax is still in the RFC, though deprecated. SPF is trying to
force us to go backwards to that era.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book: http://www.uit.co.uk/exim-book
