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Diffstat (limited to 'usr.sbin/named/man/hostname.7')
| -rw-r--r-- | usr.sbin/named/man/hostname.7 | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/usr.sbin/named/man/hostname.7 b/usr.sbin/named/man/hostname.7 new file mode 100644 index 00000000000..f19d84b4de8 --- /dev/null +++ b/usr.sbin/named/man/hostname.7 @@ -0,0 +1,110 @@ +.\" $NetBSD: hostname.7,v 1.1 1996/02/02 15:27:32 mrg Exp $ +.\" +.\" Copyright (c) 1987 The Regents of the University of California. +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms are permitted +.\" provided that the above copyright notice and this paragraph are +.\" duplicated in all such forms and that any documentation, +.\" advertising materials, and other materials related to such +.\" distribution and use acknowledge that the software was developed +.\" by the University of California, Berkeley. The name of the +.\" University may not be used to endorse or promote products derived +.\" from this software without specific prior written permission. +.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR +.\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED +.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. +.\" +.\" @(#)hostname.7 6.4 (Berkeley) 1/16/90 +.\" +.TH HOSTNAME 7 "February 16, 1994" +.UC 5 +.SH NAME +hostname \- host name resolution description +.SH DESCRIPTION +Hostnames are domains. A domain is a hierarchical, dot-separated list +of subdomains. For example, the machine \fImonet\fP, in the \fIBerkeley\fP +subdomain of the \fIEDU\fP subdomain of the Internet Domain Name System +would be represented as +.br + \fImonet\fP.\fIBerkeley\fP.\fIEDU\fP +.br +(with no trailing dot). +.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 usually performed by the library routine +.IR gethostbyname (3).) +The default method for resolving hostnames by the Internet name resolver is +to follow \s-1RFC\s+1 1535's security recommendations. Actions can be taken +by the administrator to override these recommendations and to have the +resolver behave the same as earlier, non-\s-1RFC\s+1 1535 resolvers. +.PP +The default method (using \s-1RFC\s+1 1535 guidelines) follows: +.PP +If the name consists of a single component, i.e. contains no dot, and if the +environment variable ``\s-1HOSTALIASES\s+1'' is set to the name of a file, +that file is searched for a string matching the input hostname. The file +should consist of lines made up of two strings separated by white-space, 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 there is at least one dot in the name, then the name is first tried as +is. The number of dots to cause this action is configurable by setting the +threshold using the ``\fIndots\fP'' option in +.I /etc/resolv.conf +(default: \fI1\fP). If the name ends with a dot, the trailing dot is +removed, and the remaining name is looked up (regardless of the setting of +the 'ndots' option) and no further processing is done. +.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. If neither the +search option in the +.I /etc/resolv.conf +file or the ``\s-1LOCALDOMAIN\s+1'' environment variable is used, then the +search list of domains contains only the full domain specified by the domain +option (in +.IR /etc/resolv.conf ) +or the domain used in the local hostname (see +.IR hostname (1) +and +.IR resolver (5)). +For example, if the ``\fIdomain\fP'' option is set to \fICS.Berkeley.EDU\fP, +then only CS.Berkeley.EDU will be in the search list and will be the only +domain appended to the partial hostname, for example, ``\fIlithium\fP'', +making \fIlithium.CS.Berkeley.EDU\fP the only name to be tried using the +search list. +.PP +If the search option is used in +.I /etc/resolv.conf +or the environment variable, ``\s-1LOCALDOMAIN\s+1'' is set by the user, then +the search list will include what is set by these methods. For +example, if the ``\fIsearch\fP'' option contained +.br + \fICS.Berkeley.EDU CChem.Berkeley.EDU Berkeley.EDU\fP +.br +then the partial hostname (e.g., ``\fIlithium\fP'') will be tried with each +domainname appended (in the same order specified). The resulting hostnames +that would be tried are: +.nf + \fIlithium.CS.Berkeley.EDU\fP + \fIlithium.CChem.Berkeley.EDU\fP + \fIlithium.Berkeley.EDU\fP +.fi +.PP +The environment variable ``\s-1LOCALDOMAIN\s+1'' overrides the +``\fIsearch\fP'' and ``\fIdomain\fP'' options, and if both search and domain +options are present in the resolver configuration file, then only the last +one listed is used (see +.IR resolver (5)). +.PP +If the name was not previously tried ``as is'' (i.e., it fell below the +``\fIndots\fP'' threshold or did not contain a dot), then the name as +originally provided is attempted. +.SH SEE ALSO +.IR gethostbyname (3), +.IR resolver (5), +.IR mailaddr (7), +.IR named (8) |