HOSTNAME(7)                OpenBSD 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 whitespace 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
     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
     A hostname manual page appeared in 4.2BSD.

OpenBSD 3.0                    December 30, 1993                             1
