6.3. RESERVED ADDRESS
It often is necessary to send mail to a site, without knowing any
of its valid addresses. For example, there may be mail system
dysfunctions, or a user may wish to find out a person's correct
address, at that site.
This standard specifies a single, reserved mailbox address
(local-part) which is to be valid at each site. Mail sent to that
address is to be routed to a person responsible for the site's mail
system or to a person with responsibility for general site operation.
The name of the reserved local-part address is:
Postmaster
so that "Postmaster@domain" is required to be valid.
Note: This reserved local-part must be matched without sensi-
tivity to alphabetic case, so that "POSTMASTER", "postmas-
ter", and even "poStmASteR" is to be accepted.