Mark Andrews wrote:
It was more "the only way to prevent the A lookups is to
remove the fallback".
If we ever head down this path there would need to be years
of advance notice.
We use a "1 shot" implicit MX fallback. If we were to remove this, it
would have to be done as an option.
I have no stats on hand how much of the fallback is used among
customers, but I can say that just a few months ago while assisting my
brother, the fallback was used during the time the domain did not
propagate through the net yet. I expected it in order to get the
initial setup going for his new domain setup.
Domain's don't propogate through the net. The records
propogate to authoritative servers only. There may also
be time for cached entries (positive and negative) to time
In any case, for us, I don't see any issue of making it an option
(default ON in the first few new revisions, then eventually default off)
to help in deprecating this practice.
+1 on text to deprecate the Implicit MX.
Hector Santos, CTO
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews(_at_)isc(_dot_)org