post-SRS SMTP extension for anti-spam tools/methods

SRS is a "quick hack". A long term solution can be an SMTP extension 
supporting envelope filtering anti-spam tools/methods.

My idea is two additional MAIL command:

MAIL SNDR:<initial-envelope-sender-address>
MAIL FROM:<current-sender-address>
MAIL RTRN:<envelope-return-address>


SNDR is the mailbox address of the message submitter,

FROM is the mailbox address of the message forwarder, or
the domain name of the message relay (in form: 'AT domain'),

RTRN is the envelope return path.



What do You think?

z2