HOSTNAME(7)						     Linux Programmer's Manual						       HOSTNAME(7)

NAME

       hostname - hostname resolution description

DESCRIPTION

       Hostnames  are domains, where a domain is a hierarchical, dot-separated list of subdomains; for example, the machine monet, in the Berkeley
       subdomain of the EDU subdomain of the Internet would be represented as

	   monet.Berkeley.EDU

       (with no trailing dot).

       Hostnames are often used with network client and server programs, which must generally translate the name to an	address  for  use.   (This
       task  is  generally  performed  by  either  getaddrinfo(3)  or the obsolete gethostbyname(3).)  Hostnames are resolved by the Internet name
       resolver in the following fashion.

       If the name consists of a single component, that is, contains no dot, and if the environment variable HOSTALIASES is set to the name  of  a
       file,  that file is searched for any string matching the input hostname.  The file should consist of lines made up of two white-space sepa-
       rated strings, the first of which is the hostname alias, and the second of which is the complete hostname to be substituted for that alias.
       If a case-insensitive match is found between the hostname to be resolved and the first field of a line in the file, the substituted name is
       looked up with no further processing.

       If the input name ends with a trailing dot, the trailing dot is removed, and the remaining name is looked up with no further processing.

       If the input name does not end with a trailing dot, it is looked up by searching through a list of domains until a  match  is  found.   The
       default search list includes first the local domain, then its parent domains with at least 2 name components (longest first).  For example,
       in  the	domain	CS.Berkeley.EDU,  the  name  lithium.CChem  will  be  checked  first  as   lithium.CChem.CS.Berkeley.EDU   and	 then	as
       lithium.CChem.Berkeley.EDU.   Lithium.CChem.EDU	will  not  be  tried, as there is only one component remaining from the local domain.  The
       search path can be changed from the default by a system-wide configuration file (see resolver(5)).

SEE ALSO

       gethostbyname(3), resolver(5), mailaddr(7), named(8)

COLOPHON

       This page is part of release 3.25 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/.

Linux								    2008-06-11							       HOSTNAME(7)