NAME    [Toc]    [Back]

       hostname - Host name resolution description

DESCRIPTION    [Toc]    [Back]

       Host  names 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 follows: monet.Berkeley.EDU


       Notice that there is no trailing dot.

       Host  names  are often used with network client and server
       programs, which must generally translate the  name  to  an
       address  for use. (This function is generally performed by
       the gethostbyname() function.) Host names 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 HOSTALIASES environment variable
       is  set to the name of a file, that file is searched for a
       string matching the input host name. The file should  consist
  of  lines  made  up  of  two  white-space  separated
       strings, the first of which is the host  name  alias,  and
       the  second  of which is the complete host name to be substituted
 for that alias.  If a case-insensitive  match  is
       found  between  the host name 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 ALSO    [Toc]    [Back]

       Functions: gethostbyname(3)

       Commands: named(8)



                                                      hostname(5)