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/.

Linux                                              2010-11-07                                        HOSTNAME(7)