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

NAME

       resolv.conf - resolver configuration file

SYNOPSIS

       /etc/resolv.conf

DESCRIPTION

       The  resolver is a set of routines that provide access to the Internet Domain Name System. See resolver(3RESOLV). resolv.conf is a configu-
       ration file that contains the 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 resolv.conf file contains the following configuration directives:

       nameserver	      Specifies the IPv4 or IPv6 Internet address 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 multiple servers, the resolver library queries them	in
			      the  order  listed. If no name server entries are present, the resolver library 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  name servers that follow, until each query times out. It repeats all the name servers until a maximum number of
			      retries are made.

       domain		      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 sysinfo(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.

       search		      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.

       sortlistaddresslist    Allows addresses returned by the libresolv-internal gethostbyname() to be sorted. A  sortlist  is  specified  by	IP
			      address  netmask	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 example:

				sortlist 130.155.160.0/255.255.240.0 130.155.0.0

       options		      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.

			      ndots:n		Sets a threshold floor for the number of dots which must appear in a  name  given  to  res_query()
						before	an  initial  absolute (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  abso-
						lute name before any search list elements are appended to it.

			      timeout:n 	Sets  the  amount  of  time the resolver will wait for a response from a remote name server before
			      retrans:n 	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 exponen-
						tial back off procedure where the timeout is doubled for every retransmit attempt.

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

			      rotate		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.

			      no-check-names	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  charac-
						ters.

			      inet6		Sets  RES_USE_INET6  in  _res.options.	In the Solaris BIND port, this has no effect on gethostby-
						name(3NSL). To retrieve IPv6 addresses or IPv4 addresses, use getaddrinfo(3SOCKET) instead of set-
						ting inet6.

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

       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,  sepa-
       rated by white space.

FILES

       /etc/resolv.conf

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard BIND 8.3.3	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       domainname(1M),	 sysinfo(2),  gethostbyname(3NSL),  getnameinfo(3SOCKET),  getipnodebyname(3SOCKET),  gethostname(3C),	resolver(3RESOLV),
       attributes(5)

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

SunOS 5.11							    15 Dec 2004 						    resolv.conf(4)