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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   domain   would   be   represented   as
       "monet.Berkeley.EDU".

       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 separated 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 3.54 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/.