151 lines
5.3 KiB
Groff
151 lines
5.3 KiB
Groff
.\" dhcrelay.8
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.\"
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.\" Copyright (c) 1997 The Internet Software Consortium.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\"
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of The Internet Software Consortium nor the names
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.\" of its contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
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.\" CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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.\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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.\" DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
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.\" CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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.\" LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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.\" USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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.\" ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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.\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" This software has been written for the Internet Software Consortium
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.\" by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
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.\" Enterprises. To learn more about the Internet Software Consortium,
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.\" see ``http://www.isc.org/isc''. To learn more about Vixie
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.\" Enterprises, see ``http://www.vix.com''.
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.TH dhcrelay 8
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.SH NAME
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dhcrelay - Dynamic Host Configuration Protocol Relay Agent
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.SH SYNOPSIS
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.B dhcrelay
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[
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.B -p
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.I port
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]
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[
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.B -d
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]
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[
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.B -q
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]
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[
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.B -i
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.I if0
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[
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.B ...
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.B -i
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.I ifN
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]
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]
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.I server0
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[
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.I ...serverN
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]
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.SH DESCRIPTION
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The Internet Software Consortium DHCP Relay Agent, dhcrelay, provides a
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means for relaying DHCP and BOOTP requests from a subnet to which
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no DHCP server is directly connected to one or more DHCP servers on other
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subnets.
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.SH SYSTEM REQUIREMENTS
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You must have the Berkeley
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Packet Filter (bpf) configured in your NetBSD kernel. You must have
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at least one /dev/bpf* file for each broadcast network interface that
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is attached to your system.
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.SH OPERATION
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.PP
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The DHCP Relay Agent listens for DHCP requests on all interfaces
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attached to a host, unless one or more interfaces are specified on the
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command line with the
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.I -i
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flag.
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.PP
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When a query is received, dhcrelay forwards it to the list of DHCP
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servers specified on the command line. When a reply is received, it
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is broadcast or unicast on the network from whence the original
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request came.
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.PP
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It is possible to specify a set of interfaces on which dhcrelay will
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listen, so that if dhcrelay is connected through one interface to a
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network on which there is no DHCP server, but is connected on another
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interface to a network on which there is a DHCP server, it will not
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relay DHCP and BOOTP requests from the network on which the server
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exists to that server. This is an imperfect solution.
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.SH COMMAND LINE
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.PP
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The names of the network interfaces that dhcrelay should attempt to
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configure may be specified on the command line using the
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.I -i
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option. If no interface names
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are specified on the command line dhcrelay will identify all network
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interfaces, elimininating non-broadcast interfaces if possible, and
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attempt to configure each interface.
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.PP
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If dhcrelay should listen and transmit on a port other than the
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standard (port 67), the
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.B -p
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flag may used. It should be followed by the udp port number that
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dhcrelay should use. This is mostly useful for debugging purposes.
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If the
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.B -p
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flag is specified, the relay agent will transmit responses to clients
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at a port number that is one greater than the one specified - i.e., if
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you specify
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.B -p
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67, then the relay agent will listen on port 67 and transmit to port
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68. Transmissions to servers will be sent to the same port number
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that it specified in the
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.B -p
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flag.
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.PP
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Dhcrelay will normally run in the foreground until it has configured
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an interface, and then will revert to running in the background.
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To run force dhcrelay to always run as a foreground process, the
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.B -d
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flag should be specified. This is useful when running dhcrelay under
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a debugger, or when running it out of inittab on System V systems.
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.PP
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Dhcrelay will normally print its network configuration on startup.
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This can be annoying in a system startup script - to disable this
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behaviour, specify the
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.I -q
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flag.
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.PP
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The name of at least one DHCP server to which DHCP and BOOTP requests
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should be relayed must be specified on the command line.
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.PP
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.SH SEE ALSO
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dhclient(8), dhcpd(8), RFC2132, RFC2131.
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.SH AUTHOR
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.B dhcrelay(8)
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has been written for the Internet Software Consortium
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by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
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Enterprises. To learn more about the Internet Software Consortium,
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see
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.B http://www.vix.com/isc.
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To learn more about Vixie
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Enterprises, see
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.B http://www.vix.com.
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.PP
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