|MAILADDR(7)||Linux User's Manual||MAILADDR(7)|
where a domain is a hierarchical dot-separated list of subdomains. These examples are valid forms of the same address:
John Doe <firstname.lastname@example.org>
email@example.com (John Doe)
The domain part ("monet.example.com") is a mail-accepting domain. It can be a host and in the past it usually was, but it doesn't have to be. The domain part is not case sensitive.
The local part ("john.doe") is often a username, but its meaning is defined by the local software. Sometimes it is case sensitive, although that is unusual. If you see a local-part that looks like garbage, it is usually because of a gateway between an internal e-mail system and the net, here are some examples:
(These are, respectively, an X.400 gateway, a gateway to an arbitrary internal mail system that lacks proper internet support, an UUCP gateway, and the last one is just boring username policy.)
The real-name part ("John Doe") can either be placed before <>, or in () at the end. (Strictly speaking the two aren't the same, but the difference is beyond the scope of this page.) The name may have to be quoted using "", for example, if it contains ".":
"John Q. Doe" <firstname.lastname@example.org>
This specifies that the message should be sent to hosta, from there to hostb, and finally to hostc. Many hosts disregard route-addrs and send directly to hostc.
Route-addrs are very unusual now. They occur sometimes in old mail archives. It is generally possible to ignore all but the "user@hostc" part of the address to determine the actual address.
|2017-05-03||4.2 Berkeley Distribution|