169 lines
4.5 KiB
Groff
169 lines
4.5 KiB
Groff
.\" Copyright (C) 2000 Internet Software Consortium.
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.\"
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.\" Permission to use, copy, modify, and distribute this software for any
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.\" purpose with or without fee is hereby granted, provided that the above
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.\" copyright notice and this permission notice appear in all copies.
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.\"
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.\" THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
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.\" DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
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.\" INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
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.\" INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
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.\" FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
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.\" NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
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.\" WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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.\"
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.\" $Id: lwresd.8,v 1.8 2000/10/18 22:28:42 bwelling Exp $
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.\"
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.Dd Jun 30, 2000
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.Dt LWRESD 8
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.Os BIND9 9
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.ds vT BIND 9 Programmer's Manual
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.Sh NAME
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.Nm lwresd
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.Nd lightweight resolver daemon
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.Sh SYNOPSIS
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.Nm lwresd
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.Op Fl C Ar config-file
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.Op Fl d Ar debuglevel
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.Op Fl f g s
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.Op Fl i Ar pid-file
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.Op Fl n Ar #cpus
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.Op Fl P Ar listen-port#
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.Op Fl p Ar port#
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.Op Fl t Ar directory
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.Op Fl u Ar user-id
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.Op Fl v
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.Sh DESCRIPTION
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.Nm lwresd
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is the daemon providing name lookup services to clients that use
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the BIND 9 lightweight resolver library.
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It is essentially a stripped-down, caching-only name server that
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answers queries using the BIND 9 lightweight resolver protocol
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rather than the DNS protocol.
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.Pp
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.Nm lwresd
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listens for resolver queries on a UDP port on the IPv4 loopback
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interface, 127.0.0.1.
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This means that
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.Nm lwresd
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can only be used by processes running on the local machine.
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By default UDP port number 921 is used for lightweight resolver
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requests and responses.
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.Pp
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Incoming lightweight resolver requests are decoded by
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.Nm lwresd
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which then resolves them using the DNS protocol.
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When the DNS lookup completes,
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.Nm lwresd
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encodes the answers from the name servers in the lightweight
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resolver format and returns them to the client that made the original
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request.
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.Pp
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If
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.Pa /etc/resolv.conf
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contains any
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.Sy nameserver
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entries,
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.Nm lwresd
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sends recursive DNS queries to those servers. This
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is similar to the use of forwarders in a chaching name
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server. If no
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.Sy nameserver
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entries are present, or if forwarding fails,
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.Nm lwresd
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resolves the queries autonomously starting at the
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root name servers, using a compiled-in list of root
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servers hints.
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.Pp
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The options to
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.Nm lwresd
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are as follows:
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.Bl -tag -width Ds
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.It Fl C
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use
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.Ar config-file
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as the configuration file instead of the default,
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.Pa /etc/resolv.conf .
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.It Fl d
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set the daemon's debug level to
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.Ar debuglevel .
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Debugging traces from
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.Nm lwresd
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become more verbose as the debug level increases.
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.It Fl f
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run
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.Nm lwresd
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in the foreground.
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.It Fl g
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run
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.Nm lwresd
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in the foreground and force all logging to
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.Dv stderr .
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.It Fl i
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write the daemon's process id to
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.Ar pid-file
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instead of the default pathname.
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.It Fl n
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create
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.Ar #cpus
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worker threads to take advantage of multiple CPUs.
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If no option is given,
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.Nm lwresd
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will try to determine the number of CPUs present and create
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one thread per CPU. If
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.Nm lwresd
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is unable to determine the number of CPUs, a single worker thread
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is created.
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.It Fl P
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listen for lightweight resolver queries on the loopback interface
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using UDP port
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.Ar port#
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instead of the default port number, 921.
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.It Fl p
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send DNS lookups to port number
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.Ar listen-port#
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when querying name servers.
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This provides a way of testing the lightweight resolver daemon with a
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name server that listens for queries on a non-standard port number.
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.It Fl s
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write memory usage statistics to
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.Dv stdout
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on exit.
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This option is only of interest to BIND 9 developers and may be
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removed or changed in a future release.
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.It Fl t
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tells
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.Nm lwresd
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to chroot() to
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.Ar directory
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immediately after reading its configuration file.
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.It Fl u
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run
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.Nm lwresd
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as
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.Ar user-id ,
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which is a user name or numeric id that must be present in the
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password file.
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The lightweight resolver daemon will change its user-id after it has
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carried out any privileged operations, such as writing the process-id
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file or binding a socket to a privileged port (typically any port
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less than 1024).
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.It Fl v
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report the version number and exit.
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.El
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.Sh FILES
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.Bl -tag -width /var/run/lwresd.pid -compact
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.It Pa /etc/resolv.conf
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default configuration file
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.It Pa /var/run/lwresd.pid
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default process-id file
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.El
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.Sh SEE ALSO
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.Xr named 8 ,
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.Xr lwres 3 .
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.Sh NOTES
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.Nm lwresd
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is a daemon for lightweight resolvers, not a lightweight daemon
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for resolvers.
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