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resolver(4)
NAME
  resolver - resolver configuration file

SYNOPSIS
  /etc/resolv.conf

DESCRIPTION
  The resolver is a set of routines in the C library that provide access to
  the Internet Domain Name System. The resolver configuration file
  (resolv.conf) contains information that is read by the resolver routines
  the first time they are invoked by a process. The file is designed to be
  read by humans and contains a list of keywords with values that provide
  various types of resolver information.

  The different configuration options are:

  nameserver
      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
      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
      Search list for host name lookup. By default, the search list consists
      of the local domain name.	 You can change this system wide by
      specifying search keyword followed by a list of domain names separated
      by spaces or tabs, or on a per-process basis by specifying the
      LOCALDOMAIN environment variable followed by a list of domain names
      separated by spaces or tabs.

      Most resolver queries will be attempted using each component of the
      search path in turn until a match is found.  This process might be slow
      and 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.

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

  sortlist
      Enables the sorting of addresses returned by gethostname.	 A sortlist
      comprises pairs of IP addresses and optional netmasks; each IP address
      and optional netmask are separated by a slash character (/).  The
      netmask is optional, and defaults to the current network netmask.	 You
      can specify up to 10 pairs.  For example:

	   sortlist 130.155.160.0/255.255.240.0 130.155.0.0

  options ndots:n
      Option for host name lookup.  By default, when a host name contains one
      or more dots (.), resolver looks up the name as given before applying
      the search list.	The n specifies the minimum number of dots a name
      must contain in order to be looked up as given before applying the
      search list.  The range is from 0 to 15.

      You can change the resolver options system wide by specifying options
      keyword followed a list of resolver options separated by spaces, or on
      a per-process basis by specifying the RES_OPTIONS environment variable
      followed by a list of resolver options separated by spaces.

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

  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.

FILES
  /etc/resolv.conf

SEE ALSO
  Functions: dn_comp(3), dn_expand(3), gethostbyname(3), res_init(3),
  res_mkquery(3), res_query(3), res_search(3), res_send(3)

  Files: hostname(5)

  Commands: named(8)

Index for Section 4

Alphabetical listing for R

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