HOSTNAME(7) Linux Programmer's Manual HOSTNAME(7)
hostname - hostname resolution description
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 domain would be rep-
resented as "monet.Berkeley.EDU".
Hostnames are often used with network client and server programs, which must generally
translate the name to an address for use. (This task is generally performed by either
getaddrinfo(3) or the obsolete gethostbyname(3).) Hostnames are resolved by the Internet
name resolver in the following fashion.
If the name consists of a single component, that is, contains no dot, and if the environ-
ment 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
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 a system-wide configuration file (see
gethostbyname(3), resolver(5), mailaddr(7), named(8)
This page is part of release 3.55 of the Linux man-pages project. A description of the
project, and information about reporting bugs, can be found at
Linux 2010-11-07 HOSTNAME(7)