On-Demand Mail Relay (ODMR) or Authenticated TURN (ATRN)

On-Demand Mail Relay (ODMR), also known as Authenticated TURN (ATRN), is an e-mail service that allows a user to connect to an Internet service provider ( ISP ), authenticate, and request e-mail using a dynamic IP address from any Internet connection. Simply put, ODMR is Simple Mail Transfer Protocol ( SMTP ) using dynamic IP addresses instead of static IP addresses. Once the user requests e-mail, the roles of client and server reverse, and normal SMTP operations occur.

ODMR can only be used with Internet service providers that support ODMR.