Alex van den Bogaerdt wrote:
In theory HELO a.b.x.example must have _an_ IP, but this IP
is not necessarily the IP of the peer,
[...]
It has to be _the_ name of the box connecting to you, however
you cannot verify the name of the box by verifying the name
of the interface.
What you say is essentially the same from the receiver's POV.
If you see a HELO www.example.com from IP 192.0.34.165, then
you can't reject it. Please correct me if I'm wrog.
JFTR: 192.0.34.165 = res-dom.iana.org (= all IPs of this host)
192.0.34.166 = www.example.com (= all IPs of this host)
Bye, Frank