lwresd(1M)lwresd(1M)NAMElwresd - lightweight resolver daemon
SYNOPSIS
config-file] debuglevel] pid-file] ncpus] query-port] port] directory]
user-id]
DESCRIPTION
The daemon provides name lookup services for 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 light‐
weight resolver protocol rather than the DNS protocol.
listens for resolver queries on a UDP port on the IPv4 loopback inter‐
face, 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 which then
resolves them using the DNS protocol. When the DNS lookup completes,
encodes the answers from the name servers in the lightweight resolver
format and returns them to the client that made the original request.
If the configuration file contains any entries, 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 compiled-in list of root-server hints.
Options
Use config-file as the configuration file. The default is
Set the debug level to
debuglevel. Debugging traces from become more verbose as the
debug level increases.
Run in the foreground.
Run in the foreground and force all logging to standard error.
Write the daemon's process ID to
pid-file. The default is
Create ncpus worker threads to take advantage of multiple CPUs. By
default, tries to determine the number of CPUs present and
creates one thread per CPU. If it cannot determine the num‐
ber of CPUs, it creates a single worker thread.
Send DNS lookups to port number
query-port when querying name servers. This provides a way
of testing the lightweight resolver daemon with a name server
that listens for queries on a nonstandard port number.
Listen for lightweight resolver queries on the
loopback interface using UDP port number port. The default
is port 921.
Write memory usage statistics to standard output on exit.
This option is only of interest to BIND 9 developers and may
be removed or changed in a future release.
Change root to
directory immediately after reading the configuration file
(see chroot(2)).
Run as user-id, which is a user name or numeric ID that must be
present in the password file. changes its user-id after it
has carried out any privileged operations, such as writing
the process-ID file or binding a socket to a privileged port
(typically any port less than 1024).
Note
is a daemon for lightweight resolvers, not a lightweight daemon for
resolvers.
AUTHOR
was developed by the Internet Systems Consortium (ISC).
FILES
Default resolver configuration file
Default process-id file
SEE ALSOnamed(1M), chroot(2).
available online at
available from the Internet Systems Consortium at
BIND 9.3 lwresd(1M)
