hostname(5)							   hostname(5)

NAME    [Toc]    [Back]

     hostname -	hostname resolution description

DESCRIPTION    [Toc]    [Back]

     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 subdomain of the Internet would be represented as

     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(3N).)
     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 a 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.  For example, to
     refer to the host ``matisse.painters.org''	with the alias ``henri'', use

     henri     matisse.painters.org

     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	the resolv.conf	system-wide configuration file.	 See the



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hostname(5)							   hostname(5)



     descriptions of the search	keyword	in resolver(4).

NOTE    [Toc]    [Back]

     Hostnames (and usernames) must be encoded in ASCII.

SEE ALSO    [Toc]    [Back]

     named(1M),	gethostbyname(3N), resolver(3N), hosts(4), resolver(4)


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