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resolv.conf(4)			 File Formats			resolv.conf(4)

       resolv.conf - resolver configuration file


       The  resolver  is a set of routines that	provide	access to the Internet
       Domain Name System. See resolver(3RESOLV). resolv.conf is a  configura-
       tion  file  that	 contains the information that is read by the resolver
       routines	the first time they are	invoked	by a process. The file is  de-
       signed to be human readable and contains	a list of keywords with	values
       that provide various types of resolver information.

       The resolv.conf file contains the following configuration directives:

	     Specifies the Internet address in dot-notation format of  a  name
	     server  that  the	resolver is to query. Up to MAXNS name servers
	     may be listed, one	per keyword. See <resolv.h>. If	there are mul-
	     tiple  servers,  the  resolver  library queries them in the order
	     listed. If	no name	server entries are present, the	 resolver  li-
	     brary  queries the	name server on the local machine. The resolver
	     library follows the algorithm to try  a  name  server  until  the
	     query times out.  It then tries the the name servers that follow,
	     until each	query times out. It repeats all	the name servers until
	     a maximum number of retries are made.

	     Specifies	the  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 sys-
	     info(2) or	from gethostname(3C). (Everything after	the first  `.'
	     is	 presumed  to  be  the domain name.) If	the host name does not
	     contain a domain part, the	root domain is assumed.	 You  can  use
	     the LOCALDOMAIN environment variable to override the domain name.

	     The search	list for host name lookup. The search list is normally
	     determined	from the local domain name. By	default,  it  contains
	     only  the	local domain name. You can change the default behavior
	     by	listing	the desired domain search path	following  the	search
	     keyword,  with spaces or tabs separating the names. Most resolver
	     queries will be attempted using each component of the search path
	     in	turn until a match is found. This process may be slow and will
	     generate a	lot of network traffic if the servers for  the	listed
	     domains  are  not	local.	Queries	 will time out if no server is
	     available for one of the domains.

	     The search	list is	currently limited to six domains and  a	 total
	     of	256 characters.

	     Allows  addresses	returned  by the libresolv-internal gethostby-
	     name() to be sorted. A sortlist is	specified by IP	 address  net-
	     mask  pairs.  The netmask is optional and defaults	to the natural
	     netmask of	the net. The IP	address	and optional network pairs are
	     separated	by slashes. Up to 10 pairs may be specified. For exam-


	     Allows certain internal resolver variables	to  be	modified.  The
	     syntax is

	     options option ...

	     where option is one of the	following:

	     debug Sets	RES_DEBUG in the _res.options field.

		   Sets	 a  threshold  floor for the number of dots which must
		   appear in a name given to res_query() before	an initial ab-
		   solute  (as-is)  query is performed.	See resolver(3RESOLV).
		   The default value for n is 1, which means that if there are
		   any	dots in	a name,	the name is tried first	as an absolute
		   name	before any search list elements	are appended to	it.


		   Sets	the amount of time the resolver	will wait  for	a  re-
		   sponse  from	a remote name server before retrying the query
		   by means of a different name	server.	Measured  in  seconds,
		   the default is RES_TIMEOUT. See <resolv.h>. The timeout and
		   retrans values are the starting point  for  an  exponential
		   back	 off  procedure	where the timeout is doubled for every
		   retransmit attempt.


		   Sets	the number of times the	resolver will send a query  to
		   its name servers before giving up and returning an error to
		   the calling application.
		    The	default	is RES_DFLRETRY. See <resolv.h>.

		   Sets	RES_ROTATE  in	_res.options.  The  name  servers  are
		   queried round-robin from among those	listed.	The query load
		   is spread among all listed servers, rather than having  all
		   clients try the first listed	server first every time.

		   Sets	 RES_NOCHECKNAME  in  _res.options.  This disables the
		   modern BIND checking	of incoming host names and mail	 names
		   for	invalid	 characters such as underscore (_), non-ASCII,
		   or control characters.

	     inet6 Sets	RES_USE_INET6 in _res.options.	In  the	 Solaris  BIND
		   port,  this	has  no	 effect	on gethostbyname(3NSL).	To re-
		   trieve IPv6 addresses or IPv4 addresses in mapped form, use
		   getipnodebyname(3SOCKET) instead of setting inet6.

       The domain and search keywords are mutually exclusive. If more than one
       instance	of these keywords is present, the last instance	 takes	prece-

       You can override	the search keyword of the system resolv.conf file on a
       per-process basis by setting the	environment variable LOCALDOMAIN to  a
       space-separated list of search domains.

       You  can	 amend the options keyword of the system resolv.conf file on a
       per-process basis by setting the	environment variable RES_OPTIONS to  a
       space-separated list of resolver	options.

       The keyword and value must appear on a single line. Start the line with
       the keyword, for	example, nameserver, followed by the value,  separated
       by white	space.


       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE	TYPE	     |	    ATTRIBUTE VALUE	   |
       |Interface Stability	     |Standard BIND 8.2.4	   |

       domainname(1M),	in.named(1M), sysinfo(2), gethostbyname(3NSL), getipn-
       odebyname(3SOCKET), gethostname(3C), resolver(3RESOLV)

       Vixie, Paul, Dunlap, Keven J., Karels, Michael J.  Name	Server	Opera-
       tions Guide for BIND. Internet Software Consortium, 1996.

SunOS 5.9			  10 Sep 2001			resolv.conf(4)


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