spf-discuss
[Top] [All Lists]

OT: Encrypting Proxy question: What "MAIL FROM:" address is safe to use?

2004-11-09 02:45:27
Hi All,

Is there any such thing as a universally accepted "MAIL FROM:"
envelope sender address, from the point of view of ISP MTA's accepting
emails from customers, and where the "RCPT TO:" addressee is myself
(my own MTA on which I can enforce my own rules) ?

I've written a proxy to encrypt emails between client and my server -
it removes then replaces the envelope recipients with the address of
my decrypting server, encrypts the DATA (after inserting my
RSA-encrypted session key and the list of original envelope
recipients), however, I'm not sure how I should handle the senders
email address (MAIL FROM:)     

For better protection, I would like to remove this - however - I am
not sure if all ISP's email servers are willing to accept emails from
arbitrary sender email addresses.  I suspect not all will like this -
so - is there a standard I can use?   

MAIL FROM: <>  maybe?
MAIL FROM: postmaser  maybe?
MAIL FROM: postmaser(_at_)real-senders-hostname  maybe?

Thanks in advance for all advice and pointers.  Sorry for the
off-topic post - but hey - access to a group of what's probably the
worlds leading experts able to answer my question... how could I
resist?

Kind Regards,
Chris Drake.