RESOLVER(5)                    11,                    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  configuration 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  key-
       words  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 resolver should query.  Up to MAXNS (cur-
              rently 3) name servers may be listed, one per  key-
              word.   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(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 contains only the local domain name.
              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.



November                                                        1





RESOLVER(5)                    11,                    RESOLVER(5)


              Note  that this process may be slow and will gener-
              ate 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
              Sortlist allows addresses returned by 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.

              e.g.      sortlist      130.155.160.0/255.255.240.0
              130.155.0.0

       options
              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 _res.options.

              ndots:n  -- sets a threshold for the number of dots
              which must appear in a name given to res_query (see
              resolver(3))  before an initial absolute query will
              be made.  The default for n is ``1'', meaning  that
              if  there  are any dots in a name, the name will be
              tried first as an absolute name before  any  search
              list elements are appended to it.

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

       The  search  keyword of a system's resolv.conf file can be
       overridden on a per-process basis by setting the  environ-
       ment variable ``LOCALDOMAIN'' to a space-separated list of
       search domains.

       The options keyword of a system's resolv.conf file can  be
       amended  on a per-process basis by setting the environment
       variable ``RES_OPTIONS''  to  a  space-separated  list  of
       resolver options as explained above under options.

       The  keyword  and  value must appear on a single line, and
       the keyword (e.g. nameserver) must start  the  line.   The



November                                                        2





RESOLVER(5)                    11,                    RESOLVER(5)


       value follows the keyword, separated by white space.

FILES
       /etc/resolv.conf

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

















































November                                                        3



Please look at the man2html translation issues.
man2html.pl Version 1.1, Copyright 1997, 1998 by Richard Dawe