Gordon,
mail from does not scale all that well. Imagine having to preregister
every telephone you might call from.
GF> "Calling-Card."
That's actually quite different.
RMX mechanisms require registering the MTA. That's equivalent to having
to pre-register the physical telephones that you will use.
d/
--
Dave Crocker <dcrocker-at-brandenburg-dot-com>
Brandenburg InternetWorking <www.brandenburg.com>
Sunnyvale, CA USA <tel:+1.408.246.8253>