hostname(7) - NetBSD Manual Pages

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HOSTNAME(7)                 NetBSD Reference Manual                HOSTNAME(7)


NAME

     hostname - host name 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 sub-
     domain 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(3).)  Host-
     names are resolved by the Internet name resolver in the following fash-
     ion.

     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 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 lithi-
     um.CChem.CS.Berkeley.EDU and then as lithium.CChem.Berkeley.EDU.  Lithi-
     um.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 resolv.conf(5)).


SEE ALSO

     gethostbyname(3),  resolv.conf(5),  mailaddr(7),  named(8)


HISTORY

     Hostname appeared in 4.2 BSD.

4.2 Berkeley Distribution      December 30, 1993                             1