Re: Minor isn't. It's a pardigm change

Hi Paul,
At 02:39 31-03-2008, Paul Smith wrote:
> Either:
> - toaster.example.org is going to send a message with the 
> return-path of something(_at_)toaster(_dot_)example(_dot_)org, in which case I'd 
> EXPECT toaster.example.org to have an SMTP server running on it, 
> hence an MX record would not be a bad thing, or
> - toaster.example.org is going to send a message with a null return 
> path, in which case what does it matter..
The discussion have been whether the receiver should explicitly 
specify a MX RR to determine whether it accepts mail.  If we stretch 
the MX RR requirement to a forward and reverse model, then the sender 
(toaster.example.org) also has to have a MX RR.  This means that the 
change affects both senders and receivers.  If we use a null 
return-path, the sender won't know whether there was a delivery failure.
> Personally, I can see a strong point for requiring MX records for 
> any domain which can receive mail as it removes a big ambiguity. 
> Anyone who doesn't set one up will soon notice that things aren't 
> working and will fix it. If a mail administrator is on 'talking 
> terms' with the DNS administrator enough to have an AAAA record 
> assigned to them, surely they're on talking terms enough to have an 
> MX record set up as well, especially since the DNS administrator 
> should know enough to know that one is expected.
We then have to elect whether we want a mail service as we add the 
Address record.  If we want to run a mail service later, it can be an 
administrative burden to get the MX RR added.
Regards,
-sm