[Mimedefang] Bouncing on invalid HELO/EHLO

[Jim McCullars]

I know there's a lot of controversy regarding bouncing mail where the
HELO/EHLO string doesn't match the real host name, but in reading RFC1123,
I came across this:

          Note also that the HELO argument is still required to have
          valid <domain> syntax, since it will appear in a Received:
          line; otherwise, a 501 error is to be sent.

How many people actually bounce mail based on this rule?

Jim