MirBSD manpage: mailaddr(7)

MAILADDR(7)                  BSD Reference Manual                  MAILADDR(7)


     mailaddr - mail addressing description


     Mail addresses are based on the Internet protocol listed at the end of
     this manual page. These addresses are in the general format


     where a domain is a hierarchical dot separated list of subdomains. For
     example, a valid address is:


     Unlike some other forms of addressing, domains do not imply any routing.
     Thus, although this address is specified as an Internet address, it might
     travel by an alternate route if that were more convenient or efficient.
     For example, at Berkeley, the associated message would probably go
     directly to CS over the Ethernet rather than going via the Berkeley In-
     ternet gateway.


     Under certain circumstances it may not be necessary to type the entire
     domain name. In general, anything following the first dot may be omitted
     if it is the same as the domain from which you are sending the message.
     For example, a user on "calder.berkeley.edu" could send to "eric@CS"
     without adding the "berkeley.edu" since it is the same on both sending
     and receiving hosts.


     Certain old address formats are converted to the new format to provide
     compatibility with the previous mail system. In particular,



     are allowed;


     is converted to




     is converted to


     This is normally converted back to the "host!user" form before being sent
     on for compatibility with older UUCP hosts.

Case distinctions

     Domain names (i.e., anything after the "@" sign) may be given in any mix-
     ture of upper and lower case with the exception of UUCP hostnames. Most
     hosts accept any combination of case in user names, with the notable ex-
     ception of MULTICS sites.


     Under some circumstances it may be necessary to route a message through
     several hosts to get it to the final destination. Normally this routing
     is done automatically, but sometimes it is desirable to route the message
     manually. Addresses which show these relays are termed "route-addrs".
     These use the syntax:


     This specifies that the message should be sent to "hosta", from there to
     "hostb", and finally to "hostc". This path is forced even if there is a
     more efficient path to "hostc".

     Route-addrs occur frequently on return addresses, since these are gen-
     erally augmented by the software at each host. It is generally possible
     to ignore all but the "user@hostc" part of the address to determine the
     actual sender.

     [Note: The route-addr syntax is officially deprecated in RFC 1123 and
     should not be used.]

     Many sites also support the "percent hack" for simplistic routing:


     is routed as indicated in the previous example.


     Every site is required to have a user or user alias designated
     "postmaster" to which problems with the mail system may be addressed.

Other networks

     Some other networks can be reached by giving the name of the network as
     the last component of the domain. This is not a standard feature and may
     not be supported at all sites. For example, messages to CSNET or BITNET
     sites can often be sent to "user@host.CSNET" or "user@host.BITNET",


     mail(1), sendmail(8)

     Crocker, D. H., Standard for the Format of Arpa Internet Text Messages,
     RFC 822.


     mailaddr appeared in 4.2 BSD.


     The RFC 822 group syntax ("group:user1,user2,user3;") is not supported
     except in the special case of "group:;" because of a conflict with old
     berknet-style addresses.

     Route-Address syntax is grotty.

     UUCP- and Internet-style addresses do not coexist politely.

MirBSD #10-current              June 16, 1993                                1

Generated on 2022-12-24 01:00:14 by $MirOS: src/scripts/roff2htm,v 1.113 2022/12/21 23:14:31 tg Exp $ — This product includes material provided by mirabilos.

These manual pages and other documentation are copyrighted by their respective writers; their sources are available at the project’s CVSweb, AnonCVS and other mirrors. The rest is Copyright © 2002–2022 MirBSD.

This manual page’s HTML representation is supposed to be valid XHTML/1.1; if not, please send a bug report — diffs preferred.

Kontakt / Impressum & Datenschutzerklärung