143725Scael.\" Copyright (c) 1983, 1987, 1990 The Regents of the University of California. 236737Sbostic.\" All rights reserved. 320973Smckusick.\" 443725Scael.\" %sccs.include.redist.man% 520973Smckusick.\" 6*63450Seric.\" @(#)mailaddr.7 6.7 (Berkeley) 06/16/93 736737Sbostic.\" 843725Scael.Dd 943725Scael.Dt MAILADDR 7 1043725Scael.Os BSD 4.2 1143725Scael.Sh NAME 1243725Scael.Nm mailaddr 1343725Scael.Nd mail addressing description 1443725Scael.Sh DESCRIPTION 15*63450SericMail addresses are based on the Internet protocol listed at the end of this 1631939Sbosticmanual page. These addresses are in the general format 1743725Scael.Pp 1843725Scael.Dl user@domain 1943725Scael.Pp 2031939Sbosticwhere a domain is a hierarchical dot separated list of subdomains. For 21*63450Sericexample, a valid address is: 2243725Scael.Pp 23*63450Seric.Dl eric@CS.Berkeley.EDU 2443725Scael.Pp 25*63450SericUnlike some other forms of addressing, domains do not imply any routing. 26*63450SericThus, although this address is specified as an Internet address, it might 2731939Sbostictravel by an alternate route if that were more convenient or efficient. 2831939SbosticFor example, at Berkeley, the associated message would probably go directly 29*63450Sericto CS over the Ethernet rather than going via the Berkeley Internet 3031939Sbosticgateway. 3143725Scael.Ss Abbreviation. 3231939SbosticUnder certain circumstances it may not be necessary to type the entire 3331939Sbosticdomain name. In general, anything following the first dot may be omitted 3420973Smckusickif it is the same as the domain from which you are sending the message. 35*63450SericFor example, a user on ``calder.berkeley.edu'' could send to ``eric@CS'' 3631939Sbosticwithout adding the ``berkeley.edu'' since it is the same on both sending 3731939Sbosticand receiving hosts. 3843725Scael.Ss Compatibility. 3943725Scael.Pp 4031939SbosticCertain old address formats are converted to the new format to provide 4131939Sbosticcompatibility with the previous mail system. In particular, 4243725Scael.Pp 43*63450Seric.Dl user@host 4443725Scael.Pp 45*63450Sericand 46*63450Seric.Dl user@host.domain 4743725Scael.Pp 48*63450Sericare allowed; 4943725Scael.Pp 50*63450Seric.Dl host.domain!user 51*63450Seric.Pp 5220973Smckusickis converted to 5343725Scael.Pp 54*63450Seric.Dl user@host.domain 5543725Scael.Pp 56*63450Sericand 5743725Scael.Pp 5843725Scael.Dl host!user 5943725Scael.Pp 60*63450Sericis converted to 6143725Scael.Pp 6243725Scael.Dl user@host.UUCP 6343725Scael.Pp 6431939SbosticThis is normally converted back to the ``host!user'' form before being sent 6531939Sbosticon for compatibility with older UUCP hosts. 6643725Scael.Pp 6743725Scael.Ss Case Distinctions. 6843725Scael.Pp 6931939SbosticDomain names (i.e., anything after the ``@'' sign) may be given in any mixture 7031939Sbosticof upper and lower case with the exception of UUCP hostnames. Most hosts 7131939Sbosticaccept any combination of case in user names, with the notable exception of 7231939SbosticMULTICS sites. 7343725Scael.Ss Route-addrs. 7443725Scael.Pp 7531939SbosticUnder some circumstances it may be necessary to route a message through 7631939Sbosticseveral hosts to get it to the final destination. Normally this routing 7731939Sbosticis done automatically, but sometimes it is desirable to route the message 7831939Sbosticmanually. Addresses which show these relays are termed ``route-addrs.'' 7920973SmckusickThese use the syntax: 8043725Scael.Pp 8143725Scael.Dl <@hosta,@hostb:user@hostc> 8243725Scael.Pp 8331939SbosticThis specifies that the message should be sent to hosta, from there to hostb, 8431939Sbosticand finally to hostc. This path is forced even if there is a more efficient 8531939Sbosticpath to hostc. 8643725Scael.Pp 8731939SbosticRoute-addrs occur frequently on return addresses, since these are generally 8831939Sbosticaugmented by the software at each host. It is generally possible to ignore 89*63450Sericall but the ``user@hostc'' part of the address to determine the actual 9031939Sbosticsender. 91*63450Seric.Pp 92*63450Seric[Note: the route-addr syntax is officially deprecated 93*63450Sericin RFC 1123 and should not be used.] 94*63450Seric.Pp 95*63450SericMany sites also support the ``percent hack'' for simplistic routing: 96*63450Seric.Pp 97*63450Seric.Dl user%hostc%hostb@hosta 98*63450Seric.Pp 99*63450Sericis routed as indicated in the previous example. 10043725Scael.Ss Postmaster. 10143725Scael.Pp 10231939SbosticEvery site is required to have a user or user alias designated ``postmaster'' 10320973Smckusickto which problems with the mail system may be addressed. 10443725Scael.Ss Other Networks. 10543725Scael.Pp 10631939SbosticSome other networks can be reached by giving the name of the network as the 10743725Scaellast component of the domain. 10843725Scael.Em This is not a standard feature 10943725Scaeland may 11031939Sbosticnot be supported at all sites. For example, messages to CSNET or BITNET sites 11131939Sbosticcan often be sent to ``user@host.CSNET'' or ``user@host.BITNET'' respectively. 11243725Scael.Sh SEE ALSO 11343725Scael.Xr mail 1 , 11443725Scael.Xr sendmail 8 ; 11543725Scael.br 11643725ScaelCrocker, D. H., 11743725Scael.Em Standard for the Format of Arpa Internet Text Messages, 11843725ScaelRFC822. 11943725Scael.Sh HISTORY 12043725Scael.Nm Mailaddr 12143725Scaelappeared in 4.2 BSD. 12243725Scael.Sh BUGS 12331939SbosticThe RFC822 group syntax (``group:user1,user2,user3;'') is not supported 12431939Sbosticexcept in the special case of ``group:;'' because of a conflict with old 12531939Sbosticberknet-style addresses. 12643725Scael.Pp 12723509SericRoute-Address syntax is grotty. 12843725Scael.Pp 129*63450SericUUCP- and Internet-style addresses do not coexist politely. 130