I tried the following :
S:250-AUTH PLAIN LOGIN
S:250 2.1.0 Ok
S:550 5.7.1 <[192.0.2.1]>: Helo command rejected: RFC2821 violation
As a comment to John, Victor explained when the EHLO check is being
done in the message at
I doubt that such filtering would, in general, catch much junk
mail. There might be a reason why it was implemented in this
case. It may not be a good time to ask about this as there was an
announcement about some upgrades to ietf.org servers.
The specification would be more lengthy if operational guidance about
such cases is included. Anyway, it would take more than that to fix
the incorrect recommendations which are available online.
1. The client IP address was used for the test.
ietf-smtp mailing list