lwresd

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 pro-
       cesses 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	 com-
       pletes,	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 argu-
	      ments, 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 Systems Consortium



BIND9				June 30, 2000			    LWRESD(8)