hostname - host name resolution description
Hostnames are domains, where a domain is a hierarchical,
list of subdomains; for example, the machine monet, in the
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.
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 is searched for any string matching the input hostname.
should consist of lines made up of two whitespace separated
first of which is the hostname alias, and the second of
which is the complete
hostname to be substituted for that alias. If a caseinsensitive
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
If the input name ends with a trailing dot, the trailing dot
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.
search list includes first the local domain, then its parent
at least 2 name components (longest first). For example, in
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
by a system-wide configuration file (see resolv.conf(5)).
gethostbyname(3), resolv.conf(5), mailaddr(7), named(8)
A hostname manual page appeared in 4.2BSD.
OpenBSD 3.6 December 30, 1993
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