Re: Minor is. It's not a pardigm change

John R Levine wrote:
> >   To run an email server, today, an existing host only needs to make 
> > the server software operational.  No other change is required.  For 
> > example, no coordination with DNS administration is required.
> I suppose that's still true in theory, but when's the last time you 
> saw a non-spam message sent to someone(_at_)[12(_dot_)34(_dot_)56(_dot_)78] or saw an MTA 
> deliberately configured to accept mail to dotted quad addresses? Every 
> useful mail server has at least an A record.
John, maybe I missed something in the discussion, but I thought your 
proposal was to mandate MX records for IPv6 e-mail hosts? Support for 
domain literals seems unrelated.
Requiring an MX record for every mail host certainly would be a paradigm 
shift. The historical use of the MX record is to identify which hosts 
are responsible for the incoming E-mail for a domain, not identifying 
the specific hosts that are able to accept E-mail. There are many 
situations where a sending MTA coerces the RHS of the bounce address to 
its own hostname to ensure that bounces are returned specifically to the 
sending host. This might be done for list management, capacity 
management, internal corporate organization, security, or a number of 
other reasons. If MX records were required, then they'd have to be added 
for every one one of these sending hosts. I know of many organizations 
for which this would be a significant administrative burden.
<csg>