Whoson (WHO iS ONline) is a proposed Internet
protocol that allows Internet server programs know
if a particular (dynamically allocated) IP
address is currently allocated to a known
(trusted) user and, optionally, the identity of
the said user. The protocol could be used by an
SMTP Message Transfer System in conjunction with
anti-spam-relaying filters to implement a scheme
similar to the one described here to allow roaming
customers use their "home" SMTP server to submit
email while connected from a "foreign" network.
