Short for
On-Demand Mail Relay, an
e-mail service that allows a user to request e-mail from any internet connection by using a
dynamic IP address as opposed to a
static IP address. With OMDR, the user connects to an
ISP that supports OMDR,
authenticates and then requests e-mail. When the user requests e-mail, the roles of
client and server reverse and normal
SMTP operations proceed.
ODMR also is called ATRN, short for Authenticated Turn.