RFC 822 states:
6.3. RESERVED ADDRESS It often is necessary to send mail to a site, without know- ing 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.
Likewise, RFC 5321 states:
4.5.1. Minimum Implementation [...] Any system that includes an SMTP server supporting mail relaying or delivery MUST support the reserved mailbox "postmaster" as a case- insensitive local name. [...] The requirement to accept mail for postmaster implies that RCPT commands that specify a mailbox for postmaster at any of the domains for which the SMTP server provides mail service, as well as the special case of "RCPT TO:<Postmaster>" (with no domain specification), MUST be supported. SMTP systems are expected to make every reasonable effort to accept mail directed to Postmaster from any other system on the Internet.
When a netizen encounters a domain that fails to behave accordingly, is there anything that s/he can do to compel the domain controller to enforce the RFC, besides submitting the domain to rfc-clueless.org (the replacement for rfc-ignorant.org)?