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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 forwarding
  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 daemonize).

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

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

  -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 configuration 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 operations, 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

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