RESOLVER(5)                      File Formats                      RESOLVER(5)

NAME

       resolver - resolver configuration file

SYNOPSIS

       /etc/resolv.conf

DESCRIPTION

       The  resolver  is  a  set of routines in the C library (resolv(3)) that
       provide access to the Internet Domain Name System.  The  resolver  con‐
       figuration  file contains information that is read by the resolver rou‐
       tines 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.

       On a normally configured system this file should not be necessary.  The
       only name server to be queried will be on the local machine, the domain
       name is determined from the host name, and the domain  search  path  is
       constructed from the domain name.

       The different configuration options are:

       nameserver
              Internet address (in dot notation) of a name server that the re‐
              solver 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  name����
              server  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(2); the domain part is taken to  be
              everything  after the first `.'.  Finally, if the host name does
              not contain a domain part, the root domain is assumed.

       search Search list for host-name lookup.  The search list  is  normally
              determined  from  the  local  domain name; by default, it begins
              with the local domain name, then successive parent domains  that
              have  at  least  two  components  in  their  names.  This may be
              changed 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.  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.

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

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

       The keyword and value must appear on a single  line,  and  the  keyword
       (e.g.  nameserver) must start the line.  The value follows the keyword,
       separated by white space.

FILES

       /etc/resolv.conf

SEE ALSO

       gethostbyname(3N), resolver(3), hostname(7), named(8)
       Name Server Operations Guide for BIND



GNO                             7 February 1999                    RESOLVER(5)