In message <53cfbb29.7040...@chrysler.com>, Kevin Darcy writes: > Potentially dumb question: what does this "magic meaning" MX target > (".") offer, that a target resolving to a null address (0.0.0.0 and/or > ::0) does not? No protocol or code changes required.
And just to be clear, nullmx as proposed does not required any code changes and never has. It's simply recognizing a (to me at least) serendipitous confluence of existing attributes of DNS and SMTP. No new protocols are being invented and no deviation from those two standards is being suggested. Remember, considerate receivers have been adding this MX to their zones for many years and senders, whether they know it or not, having been automatically reaping the benefits as a consequence. This is about as close as it gets to a free lunch on the Internet. Mark. _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop