Hector Santos wrote:
True. But if you could mandate that NOT having an MX record makes the
domain NOT valid for mail, then it might be easier to filter out some
junk. Also, it stops mail senders (sending bounce messages normally)
*arbitrarily* choosing to try to send the mail to a host.
- Service Port
- Valid Recipient
At the very least, the service port is a major consideration.
In short, having a MX record does not make you a valid mail host until
everything else about the process is valid.
It's "arbitrary" because there's no way to set up a host name which
WON'T get mail (other than to do something extra such as set up a dummy
MX record, which would make anyone think that the name SHOULD get mail
contrary to the actual reason for doing it), so simply setting up a host
name causes the incorrect implication that you want to get mail on that
Yes, you can say that the lack of a waiting service port means it isn't
a mail host - but it DOESN'T. It means that it isn't a mail host *now*.
It might be in 2 minutes, or it might never be - there's no way of knowing.
If there was some mandated, standard way of advertising that there
*should* be a service on a certain port, then that would work, but IMHO,
an MX record could do just that for port 25.
VPOP3 - POP3/SMTP/IMAP4/Webmail Email server for Windows