HP-UX Reference (11i v1 05/09) - 1M System Administration Commands A-M (vol 3)

l
lwresd(1M) lwresd(1M)
NAME
lwresd - lightweight resolver daemon
SYNOPSIS
lwresd [-C config-file][
-d debuglevel][-fgs][-i pid-file][-n #cpus][
-P query-port#][-p port#]
[
-t directory][-u user-id]
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
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
/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 compiled-in list of root servers hints.
Options
-C config-file
This option is used to use config-file as the configuration file instead of the default,
/etc/resolv.conf
.
-d debuglevel
This option is used to set the daemon’s debug level to debuglevel. Debugging traces from
lwresd become more verbose as the debug level increases.
-f This option is used to run lwresd in the foreground.
-g This option is used to run lwresd in the foreground and force all logging to
stderr.
-i pid-file
This option is used to write the daemon’s process id to pid-file instead of the default path-
name.
-n #cpus This option is used to create #cpus worker threads to take advantage of multiple CPUs. If
no option is given, lwresd will try to determine the number of CPUs present and create
one thread per CPU. If lwresd is unable to determine the number of CPUs, a single
worker thread is created.
-P query-port#
This option is used to 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# This option is used to listen for lightweight resolver queries on the loopback interface using
UDP port port# instead of the default port number, 921.
-s This option is used to write memory usage statistics to stdout on exit. This option is only
of interest to BIND 9 developers and may be removed or changed in a future release.
-t directory
This option tells lwresd to chroot() to directory immediately after reading its
configuration file.
-u user-id
This option is used to run lwresd as user-id, which is a user name or numeric id that
must be present in the password file. The lightweight resolver daemon will change 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).
HP-UX 11i Version 1: September 2005 − 1 − Hewlett-Packard Company Section 1M−−469