Richard Munroe - 2006-04-11 14:32:58
According to the SMTP RFCs the return path header:
(1) is not normally inserted by the originating mailer, it is inserted by the delivering server and
(2) is of the form:
Return-Path: <--return--path-goes-here-->
with the brackets required.
I suspect that inserting the Return-Path at the point of origin is harmless, since I think that the delivering SMTP server is free to remove the one put there originally. But IF you're going to put it into the header, the return address should be bracketted.
Dick Munroe