Role as identifier[edit]

A mailbox provider is the administrator of the registered domain name that forms the domain-part of its email addresses. As such, it controls the MX records that specify which hosts will receive email destined to those addresses. The operators of those hosts define the meaning of the local-part of an address by associating it to a mailbox, which in turn can be associated to a user.^[10] The mailbox provider also specifies how users can read their mail, possibly creating SRV records to ease email client configuration, or giving detailed instructions.


Email addresses are convenient tokens for identifying people, even at web sites unrelated to email. In fact, they are unique, and allow password reminders to be sent at will.


From a bureaucracy-oriented point of view, there is no formal undertaking beyond domain name registration. This role is based on IETF standards, and, unlike X.400 and other ITU-T works, in and of itself requires no arrangements with local authorities. The notion of Administration Management Domain (ADMD) is derived afterwards, from empirical evidence.^[2] However, local authorities concerned with Internet privacy issues may add rules and requisites on top of the original Internet email design.