Let me see if I can summarise the crux of the matter, here.
Regardless of what the RFCs say about return address validity, it seems like a
reasonable local policy to reject mail that has an invalid return address.
Arguments over what the RFCs say on the matter are largely red herrings: the
sender need not be in violation of the RFCs to justify a "refuse" policy.
The problem arises in actually determining the validity of any address. The
only explicit mechanism that SMTP ever had for verifying addresses was the
VRFY command, but it has fallen out of favour. Attempting to verify an
address via SMTP using any other technique is a configuration and
implementation dependent hack. Nothing in the RFCs requires that the "MAIL
From" and "RCPT To" dialogue actually divulge the validity of any recipient
address, although it's arguably "good behaviour" to do so.
So do we suggest that VRFY ought to be revived as a return-path validity
checker? Does this benefit outweigh the disadvantages for which VRFY has been
depreciated in the first place?
Or am I misunderstanding this argument?
Regards,
TFBW
_______________________________________________
Asrg mailing list
Asrg(_at_)ietf(_dot_)org
https://www1.ietf.org/mailman/listinfo/asrg