RFC 822: Address Specification

The syntax for addresses is given as follows:

address = mailbox ; one addressee / group ; named list
group = phrase ":" [#mailbox] ";"
mailbox = addr-spec ; simple address / phrase route-addr ; name & addr-spec
route-addr = "<" [route] addr-spec ">"
route = 1#("@" domain) ":" ; path-relative
addr-spec = local-part "@" domain ; global address
local-part = word *("." word) ; uninterpreted ; case-preserved
domain = sub-domain *("." sub-domain)
sub-domain = domain-ref / domain-literal
domain-ref = atom ; symbolic reference

For an example of addresses used in an RFC 822 message, see Simple Internet Mail Message: An Example.

Address Semantics

A mailbox is defined as a conceptual entity that receives mail, and does not necessarily store files; a mailbox could, for example, pass mail directly on to a printer rather than storing it on disk.

A mailbox specification is defined as consisting of a person, system or process name reference, a domain-dependent string, and a name-domain reference, where the name reference is optional.