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HOSTNAME(7)	     BSD Miscellaneous Information Manual	   HOSTNAME(7)

     hostname -- host name resolution description

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


     (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).)  Host-
     names are resolved	by the Internet	name resolver in the following fash-

     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 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 com-
     plete 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

     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 re-
     maining from the local domain.  The search	path can be changed from the
     default by	a system-wide configuration file (see resolver(5)).

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

     Hostname appeared in 4.2BSD.

BSD			       December	30, 1993			   BSD


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