On Sun, Dec 06, 2015 at 04:01:23PM +0100, sb wrote:
> >It's now obvious that you're talking about the client hostname, not
> >the sender domain.
Standard email/Postfix terminology:
SMTP *client* - The connecting machine
Envelope *sender* - The email address in the SMTP "MAIL FROM" command
Envelope *recipient* - An email address in one of the SMTP "RCPT TO"
commands
> It is the machine that first hit my server.
At least on this list That's called the SMTP client, and it is less
confusing for everyone if we keep it that way.
> In my church, that's the sending machine.
Your religion or lack thereof is not pertinent here.
> No, I won't wait for the FROM header:
The *envelope* sender is available before the From *header*.
> such junk must be rejected upfront.
SMTP clients frequently and legitimately have FQDNs without MX
records and without an SMTP listener at the same outbound IP address.
You can insist that the envelope sender to be a real domain, but
if you want to avoid blocking a sizable fraction of legitimate
email, you cannot insist the client FQDN be an email receiving
domain. That's just not how things work on the Internet we have.
Wishful thinking won't get you a different Internet.
--
Viktor.
