HP-UX Reference (11i v3 07/02) - 1M System Administration Commands A-M (vol 3)

l
lwresd(1M) lwresd(1M)
(BIND 9.3)
NAME
lwresd - lightweight resolver daemon
SYNOPSIS
lwresd [-fgs][-C
config-file][-d debuglevel][-i pid-file][
-n ncpus][-P query-port][-p port]
[
-t directory][-u
user-id]
DESCRIPTION
The
lwresd 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
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
lwresd which then resolves them using the DNS
protocol. When the DNS lookup completes,
lwresd
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
/etc/resolv.conf
configuration file contains any nameserver entries, lwresd sends recur-
sive 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 start-
ing at the root name servers, using a compiled-in list of root-server hints.
Options
-C config-file
Use config-file as the configuration file. The default is
/etc/resolv.conf.
-d debuglevel
Set the debug level to debuglevel. Debugging traces from lwresd become more verbose as the
debug level increases.
-f Run lwresd in the foreground.
-g Run lwresd in the foreground and force all logging to standard error.
-i pid-file
Write the daemon’s process ID to pid-file. The default is
/var/run/lwresd.pid.
-n ncpus
Create ncpus worker threads to take advantage of multiple CPUs. By default, lwresd tries to
determine the number of CPUs present and creates one thread per CPU. If it cannot determine
the number of CPUs, it creates a single worker thread.
-P query-port
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 non-
standard port number.
-p port Listen for lightweight resolver queries on the loopback interface using UDP port number port.
The default is port 921.
-s 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.
-t directory
Change root to directory immediately after reading the configuration file (see chroot(2)).
-u user-id
Run as user-id, which is a user name or numeric ID that must be present in the password file.
lwresd 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
lwresd is a daemon for lightweight resolvers, not a lightweight daemon for resolvers.
HP-UX 11i Version 3: February 2007 − 1 − Hewlett-Packard Company 493