Paul Vixie wrote:
- many ISPs won't let you forward or submit mail through someone
else's SMTP server, even if you have permission to do so. so you
can't forward your mail through your "home" ISP's mail server to
allow the "mail from" check to work.
in that case you'd be wise to not insert a MAIL-FROM MX for your
The vast majority of users do not have the ability to make that decision.
The curious thing is that it is in an ISP's best interests _not_ to
implement this draft, since doing so will likely mark nomadic users' email
as suspect and potentially lose a customer. Most companies only support the
"public good" to the extent it doesn't cost them any revenue.