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mailaddr(7) [centos man page]

MAILADDR(7)							Linux User's Manual						       MAILADDR(7)

NAME
mailaddr - mail addressing description DESCRIPTION
This manual page gives a brief introduction to SMTP mail addresses, as used on the Internet. These addresses are in the general format user@domain where a domain is a hierarchical dot-separated list of subdomains. These examples are valid forms of the same address: eric@monet.berkeley.edu Eric Allman <eric@monet.berkeley.edu> eric@monet.berkeley.edu (Eric Allman) The domain part ("monet.berkeley.edu") 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 ("eric") 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: "surname/admd=telemail/c=us/o=hp/prmd=hp"@some.where USER%SOMETHING@some.where machine!machine!name@some.where I2461572@some.where (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 ("Eric Allman") 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 ".": "Eric P. Allman" <eric@monet.berkeley.edu> Abbreviation. Many mail systems let users abbreviate the domain name. For instance, users at berkeley.edu may get away with "eric@monet" to send mail to Eric Allman. This behavior is deprecated. Sometimes it works, but you should not depend on it. Route-addrs. In the past, sometimes one had to route a message through several hosts to get it to its final destination. Addresses which show these relays are termed "route-addrs". These use the syntax: <@hosta,@hostb:user@hostc> 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. Postmaster. Every site is required to have a user or user alias designated "postmaster" to which problems with the mail system may be addressed. The "postmaster" address is not case sensitive. FILES
/etc/aliases ~/.forward SEE ALSO
binmail(1), mail(1), mconnect(1), aliases(5), forward(5), sendmail(8), vrfy(8) RFC 2822 (Internet Message Format) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. 4.2 Berkeley Distribution 2004-09-15 MAILADDR(7)

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MAILADDR(7)					       BSD Miscellaneous Information Manual					       MAILADDR(7)

NAME
mailaddr -- mail addressing description DESCRIPTION
Mail addresses are based on the Internet protocol listed at the end of this manual page. These addresses are in the general format user@domain where a domain is a hierarchical dot separated list of subdomains. For example, a valid address is: eric@CS.Berkeley.EDU 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 proba- bly go directly to CS over the Ethernet rather than going via the Berkeley Internet gateway. Abbreviation. 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. Compatibility. Certain old address formats are converted to the new format to provide compatibility with the previous mail system. In particular, user@host and user@host.domain are allowed; host.domain!user is converted to user@host.domain and host!user is converted to user@host.UUCP 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 mixture of upper and lower case with the exception of UUCP hostnames. Most hosts accept any combination of case in user names, with the notable exception of MULTICS sites. Route-addrs. 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: <@hosta,@hostb:user@hostc> 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 generally 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: user%hostc%hostb@hosta is routed as indicated in the previous example. Postmaster. 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'' respectively. SEE ALSO
mail(1), sendmail(8) Crocker, D. H., Standard for the Format of Arpa Internet Text Messages, RFC822. HISTORY
Mailaddr appeared in 4.2BSD. BUGS
The RFC822 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. BSD
June 16, 1993 BSD
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