resolv.conf(4)						     Kernel Interfaces Manual						    resolv.conf(4)

NAME

       resolv.conf - Resolver configuration file

SYNOPSIS

       /etc/resolv.conf

DESCRIPTION

       The resolver is a set of routines in the C library (resolver(4)) that provide access to the Internet Domain Name System.  The resolver con-
       figuration file contains information that is read by the resolver routines the first time they are invoked  by  a  process.   The  file	is
       designed to be human readable and contains a list of keywords with values that provide various types of resolver information.

       The  keyword  and value must appear on a single line, and the keyword (for example, nameserver) must start the line.  The value follows the
       keyword, separated by white space. For example: keyword value

       The file format is as follows: nameserver Address

       Internet address (in dot notation) of a name server that the resolver should query.  Up to MAXNS (currently 3) name servers may be  listed,
       one  per  keyword.   If	there  are  multiple servers, the resolver library queries them in the order listed.  If no nameserver entries are
       present, the default is to use the name server on the local machine.  (The algorithm used is to try a name server, and if the  query  times
       out,  try the next, until out of name servers, then repeat trying all the name servers until a maximum number of retries are made).  domain
       DomainName

       Local domain name.  Most queries for names within this domain can use short names relative to the local domain.	 If  no  domain  entry	is
       present,  the  domain is determined from the local host name returned by gethostname(); the domain part is taken to be everything after the
       first . (dot).  Finally, if the host name does not contain a domain part, the root domain is assumed.  search Domain_Name1 DomainName2 ...

       Search list for host-name lookup.  Up to six domains (separated by spaces or tabs) with a total of 256 characters can be specified.  If	no
       search entry is present, the search list consists of the local domain name.

       Most  resolver queries will be attempted using each component of the search path in turn until a match is found. Note that this process may
       be slow and will generate a lot of network traffic if the servers for the listed domains are not local, and that queries will time  out	if
       no server is available for one of the domains.

       You can also specify a search list on a per-process basis by specifying the LOCALDOMAIN environment variable. See resolver(4).

       The  domain  and  search  keywords  are mutually exclusive.  If more than one instance of these keywords is present, the last instance will
       override.  options allow_special all | { char }

       Option for defining valid characters in hostnames.  Specify all to disable hostname checking (allow all characters)  or	define	a  set	of
       valid  characters  by using the { char } syntax, where char is the character you want to allow.  For example, you can allow the semicolon,
       underscore, and colon characters by using { ; \_ : }.

       Disabling hostname checking altogether is not recommended.  By default, the allow_special option is not set and strict hostname checking is
       enforced.  options ndots:n

       Option  for  hostname  lookup.  The n specifies the minimum number of dots a name must contain in order for resolver to look up the name as
       given.  If the lookup fails, the search list (if specified) is applied. The range for n is from 0 to 15.  If no options entry  is  present,
       the minimum number of dots is 1.

       You can also specify the number of dots on a per-process basis by using the RES_OPTIONS environment variable. See resolver(4).

CAUTIONS

       Any white space entered after the domain name is not ignored but is interpreted as part of the domain name.

RELATED INFORMATION

       Commands: named(8)

       Functions:  gethostbyname(3), resolver(4)

       Files: hostname(5) delim off

																    resolv.conf(4)