[Top] [All Lists]

Re: current usage of AAAA implicit MX?

2008-04-07 12:22:39

Dave Crocker wrote:

A side discussion about history might be interesting, but I'll suggest that it should not really be a factor for the current discussion. The reasons are:

1. It has a substantial installed base of use now.

2. There is a benefit in the feature, by virtue of reducing the effort to create and email receiving service, and in some environment the reduction is quite significant.

3. It is not generally recognized as causing any problems now.

What we need to do with this thread is end it.

If you are suggesting to drop the proposal, then +1.

This is definitely way too much (and important too) to throw into 2821bis at the last minute. I vote to nix it and if anything, the text I provided or similar regarding a "reminder" that IPv6 need to maintain SMTP compatible with IPv4 at all levels as we know it today, especially in the area of IPv4 based responses.

   IPv6 senders connecting to IPv4 systems MUST be aware that IPv4
   systems are ignorant of IPv6 technology and therefore SHOULD
   make it possible to comply with IPv4 SMTP protocol
   expectations to allow for responses.  This implies that
   IPv6 senders sending mail to IPv4 SHOULD have A records
   resulting from explicit MX queries or a A record resulting
   from a implicit MX.

You, John and Tony would be a better judge, but I think a simple statement like above is reasonable because it keeps with the compatibility requirements of current SMTP IPv4 systems.

If IPv6 systems or Hybrid are hitting our MTA/MSA software, the last thing I want to see happen is we rejected it because the client is not reachable come BOUNCE or come a user response back to the client domain.

I sincerely hope this is acceptable, if not, I am eager to learn why you don't think so.


Hector Santos, CTO