Section: BIND9 (8)
Updated: June 30, 2000
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lwresd - lightweight resolver daemon
lwresd [-C config-file] [-d debug-level] [-f] [-g] [-i pid-file] [-n #cpus] [-P port] [-p port] [-s] [-t directory] [-u user] [-v]
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.
listens for resolver queries on a UDP port on the IPv4 loopback interface, 127.0.0.1. This means that
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,
encodes the answers in the lightweight resolver format and returns them to the client that made the request.
sends recursive DNS queries to those servers. This is similar to the use of forwarders in a caching name server. If no
entries are present, or if forwarding fails,
resolves the queries autonomously starting at the root name servers, using a built-in list of root server hints.
- -C config-file
as the configuration file instead of the default,
- -d debug-level
Set the daemon's debug level to
debug-level. Debugging traces from
become more verbose as the debug level increases.
Run the server in the foreground (i.e. do not daemonize).
Run the server in the foreground and force all logging to
- -n #cpus
worker threads to take advantage of multiple CPUs. If not specified,
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.
Write memory usage statistics to
This option is mainly of interest to BIND 9 developers and may be removed or changed in a future release.
- -t directory
after processing the command line arguments, but before reading the configuration file.
This option should be used in conjunction with the
option, as chrooting a process running as root doesn't enhance security on most systems; the way
is defined allows a process with root privileges to escape a chroot jail.
- -u user
after completing privileged operations, such as creating sockets that listen on privileged ports.
Report the version number and exit.
The default configuration file.
The default process-id file.
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- SEE ALSO
linux.jgfs.net manual pages