On Tue, 10 Aug 2004, David Blacka wrote:
It is more credible for me to believe that there is DNS software that won't
fall back to TCP, or that there are some that don't actually allocate 64k
(the actual maximum) of space for receiving a message.
The issue is more operational, there will be quite a bit of resistance by
site security admins to open up TCP port 53 for queries of that size, and
even more resitance by sites that receive A LOT of mail to accept the
possibility of making outbound TCP queries for large number of incoming
messages.
-Rand