IETF's MARID working-group will make a decision between the competing email caller-ID systems.

The IETF already has received several proposals outlining ways to reduce spam by authenticating e-mail servers. Microsoft says it will submit to the IETF its Caller ID for E-mail Specification, which outlines a scheme for thwarting e-mail address spoofing. Yahoo is expected to submit an alternative proposal called DomainKeys, which use digital signatures to authenticate e-mail servers. Despite market pressure, IETF officials say they are unlikely to adopt a proposal from Microsoft or Yahoo without making significant changes to it.