HOSTNAME(7)                     Domain/OS BSD                      HOSTNAME(7)



NAME
     hostname - host name resolution description

DESCRIPTION
     Hostnames are domains, where a domain is a hierarchical, dot-separated
     list of subdomains.  In the following example, "monet" is the machine,
     "Berkeley" is the subdomain of the "EDU" subdomain of the ARPANET:

               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 function
     is generally performed by the library routine gethostbyname(3).)
     Hostnames are resolved by the internet name resolver in the following
     fashion.

     If the name consists of a single component, i.e. contains no dot, and if
     the environment variable "HOSTALIASES" is set to the name of a file, that
     file is searched for an 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-sensitive
     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 in
     the local domain and its parent domains until either a match is found or
     fewer than two components of the local domain remain.  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.

SEE ALSO
     gethostbyname(3), resolver(5), mailaddr(7), named(8), RFC883
     Configuring and Managing TCP/IP