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diff --git a/man7/hostname.7 b/man7/hostname.7 new file mode 100644 index 0000000..60940ba --- /dev/null +++ b/man7/hostname.7 @@ -0,0 +1,97 @@ +.\" Copyright (c) 1987, 1990, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" SPDX-License-Identifier: BSD-4-Clause-UC +.\" +.\" @(#)hostname.7 8.2 (Berkeley) 12/30/93 +.\" $FreeBSD: src/share/man/man7/hostname.7,v 1.7 2004/07/03 18:29:23 ru Exp $ +.\" +.\" 2008-06-11, mtk, Taken from FreeBSD 6.2 and modified for Linux. +.\" +.TH hostname 7 2022-10-30 "Linux man-pages 6.05.01" +.SH NAME +hostname \- hostname resolution description +.SH DESCRIPTION +Hostnames are domains, where a domain is a hierarchical, dot-separated +list of subdomains; for example, the machine "monet", in the "example" +subdomain of the "com" domain would be represented as "monet.example.com". +.PP +Each element of the hostname must be from 1 to 63 characters long and the +entire hostname, including the dots, can be at most 253 characters long. +Valid characters for hostnames are +.BR ASCII (7) +letters from +.I a +to +.IR z , +the digits from +.I 0 +to +.IR 9 , +and the hyphen (\-). +A hostname may not start with a hyphen. +.PP +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 +.BR getaddrinfo (3) +or the obsolete +.BR gethostbyname (3).) +.PP +Hostnames are resolved by the NSS framework in glibc according +to the +.B hosts +configuration in +.BR nsswitch.conf . +The DNS-based name resolver +(in the +.B dns +NSS service module) resolves them in the following fashion. +.PP +If the name consists of a single component, that is, contains no dot, +and if the environment variable +.B 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. +.PP +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. +.PP +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.example.com, the name lithium.cchem will be checked first +as lithium.cchem.cs.example and then as lithium.cchem.example.com. +lithium.cchem.com 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 +.BR resolver (5)). +.SH SEE ALSO +.BR getaddrinfo (3), +.BR gethostbyname (3), +.BR nsswitch.conf (5), +.BR resolver (5), +.BR mailaddr (7), +.BR named (8) +.PP +.UR http://www.ietf.org\:/rfc\:/rfc1123.txt +IETF RFC\ 1123 +.UE +.PP +.UR http://www.ietf.org\:/rfc\:/rfc1178.txt +IETF RFC\ 1178 +.UE +.\" .SH HISTORY +.\" Hostname appeared in +.\" 4.2BSD. |