When SPF is incompatible with Sender-ID

You can use SPF records and a custom DNS server to allow SPF-aware
recipients to verify signed envelope return paths using the exists
mechanism. This SPF record does not work for Sender-ID because the PRA
will not be signed so will FAIL.

Tony.
-- 
f.a.n.finch  <dot(_at_)dotat(_dot_)at>  http://dotat.at/
BERWICK ON TWEED TO WHITBY: WEST OR SOUTHWEST 2 OR 3 INCREASING 3 OR 4. FAIR.
GOOD. SLIGHT OR SMOOTH.