LWRESD(8)                                               LWRESD(8)


NAME
       lwresd - lightweight resolver daemon

SYNOPSIS
       lwresd  [  -C config-file ]  [ -d debug-level ]  [ -f ]  [
       -g ]  [ -i pid-file ]  [ -n #cpus ]  [ -P  port  ]   [  -p
       port ]  [ -s ]  [ -t directory ]  [ -u user ]  [ -v ]

DESCRIPTION
       lwresd  is  the  daemon  providing name lookup services to
       clients that use the BIND 9 lightweight resolver  library.
       It  is  essentially  a  stripped-down,  caching-only  name
       server that answers queries using the BIND  9  lightweight
       resolver protocol rather than the DNS protocol.

       lwresd  listens  for resolver queries on a UDP port on the
       IPv4 loopback interface, 127.0.0.1. This means that lwresd
       can  only  be  used  by  processes  running  on  the local
       machine. By default  UDP  port  number  921  is  used  for
       lightweight resolver requests and responses.

       Incoming  lightweight resolver requests are decoded by the
       server which then resolves them using  the  DNS  protocol.
       When  the DNS lookup completes, lwresd encodes the answers
       in the lightweight resolver format and returns them to the
       client that made the request.

       If   /etc/resolv.conf  contains  any  nameserver  entries,
       lwresd sends recursive DNS queries to those servers.  This
       is  similar  to  the  use  of forwarders in a caching name
       server. If no nameserver entries are present, or  if  for-
       warding  fails,  lwresd  resolves the queries autonomously
       starting at the root name servers, using a  built-in  list
       of root server hints.

OPTIONS
       -C config-file
              Use  config-file  as the configuration file instead
              of the default, /etc/resolv.conf.

       -d debug-level
              Set  the  daemon's  debug  level  to   debug-level.
              Debugging traces from lwresd become more verbose as
              the debug level increases.

       -f     Run the server in the foreground (i.e. do not  dae-
              monize).

       -g     Run the server in the foreground and force all log-
              ging to stderr.

       -n #cpus
              Create #cpus worker threads to  take  advantage  of
              multiple CPUs. If not specified, lwresd will try to



BIND9                     June 30, 2000                         1





LWRESD(8)                                               LWRESD(8)


              determine the number of CPUs present and create one
              thread  per  CPU.  If it is unable to determine the
              number of CPUs, a single worker thread will be cre-
              ated.

       -P port
              Listen  for  lightweight  resolver  queries on port
              port. If not specified, the default is port 921.

       -p port
              Send DNS lookups to port port.  If  not  specified,
              the  default  is  port  53.  This provides a way of
              testing the lightweight resolver daemon with a name
              server  that  listens for queries on a non-standard
              port number.

       -s     Write memory usage statistics to stdout on exit.

              Note: This option is mainly of interest to  BIND  9
              developers  and  may  be  removed  or  changed in a
              future release.


       -t directory
              chroot() to directory after processing the  command
              line  arguments,  but before reading the configura-
              tion file.

              Warning: This option should be used in  conjunction
              with  the -u option, as chrooting a process running
              as root doesn't enhance security on  most  systems;
              the  way  chroot() is defined allows a process with
              root privileges to escape a chroot jail.


       -u user
              setuid() to user after completing privileged opera-
              tions,  such  as  creating  sockets  that listen on
              privileged ports.

       -v     Report the version number and exit.

FILES
       /etc/resolv.conf
              The default configuration file.

       /var/run/lwresd.pid
              The default process-id file.

SEE ALSO
       named(8), lwres(3), resolver(5).

AUTHOR
       Internet Software Consortium



BIND9                     June 30, 2000                         2