Server is running sendmail 8.14
From any machine:
$ telnet mydomain.com 25
HELO mydomain.com
MAIL FROM: <me@mydomain.com>
RCPT TO: <me@mydomain.com>
DATA
this is spam
.
How do I require authentication for any mail that claims to be from a local domain?
This seems like a no-brainer anti-spam feature.
FROM TO RESULT
any non-local "Relaying denied. Proper authentication required."
non-local local success [1]
local local success [2]
[1] This is acceptable. Outsiders can send to local users without any kind of authentication. Various DNS checks can be done.
[2] This is the problem. Why should I allow anyone to mail a local user while claiming to be a local user?