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diff --git a/server/dhcpd.8 b/server/dhcpd.8 deleted file mode 100644 index c0f9aa9a..00000000 --- a/server/dhcpd.8 +++ /dev/null @@ -1,308 +0,0 @@ -.\" dhcpd.8 -.\" -.\" Copyright (c) 1995, 1996 The Internet Software Consortium. -.\" All rights reserved. -.\" -.\" Redistribution and use in source and binary forms, with or without -.\" modification, are permitted provided that the following conditions -.\" are met: -.\" -.\" 1. Redistributions of source code must retain the above copyright -.\" notice, this list of conditions and the following disclaimer. -.\" 2. Redistributions in binary form must reproduce the above copyright -.\" notice, this list of conditions and the following disclaimer in the -.\" documentation and/or other materials provided with the distribution. -.\" 3. Neither the name of The Internet Software Consortium nor the names -.\" of its contributors may be used to endorse or promote products derived -.\" from this software without specific prior written permission. -.\" -.\" THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND -.\" CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, -.\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF -.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE -.\" DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR -.\" CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT -.\" LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF -.\" USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND -.\" ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, -.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT -.\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF -.\" SUCH DAMAGE. -.\" -.\" This software has been written for the Internet Software Consortium -.\" by Ted Lemon <mellon@fugue.com> in cooperation with Vixie -.\" Enterprises. To learn more about the Internet Software Consortium, -.\" see ``http://www.isc.org/isc''. To learn more about Vixie -.\" Enterprises, see ``http://www.vix.com''. -.TH dhcpd 8 -.SH NAME -dhcpd - Dynamic Host Configuration Protocol Server -.SH SYNOPSIS -.B dhcpd -[ -.B -p -.I port -] -[ -.B -f -] -[ -.B -d -] -[ -.B -cf -.I config-file -] -[ -.B -lf -.I lease-file -] -[ -.I if0 -[ -.I ...ifN -] -] -.SH DESCRIPTION -The Internet Software Consortium DHCP Server, dhcpd, implements the -Dynamic Host Configuration Protocol (DHCP) and the Internet Bootstrap -Protocol (BOOTP). DHCP allows hosts on a TCP/IP network to request -and be assigned IP addresses, and also to discover information about -the network to which they are attached. BOOTP provides similar -functionality, with certain restrictions. -.SH OPERATION -.PP -The DHCP protocol allows a host which is unknown to the network -administrator to be automatically assigned a new IP address out of a -pool of IP addresses for its network. In order for this to work, the -network administrator allocates address pools in each subnet and -enters them into the dhcpd.conf(5) file. -.PP -On startup, dhcpd reads the -.IR dhcpd.conf -file and stores a list of available addresses on each subnet in -memory. When a client requests an address using the DHCP protocol, -dhcpd allocates an address for it. Each client is assigned a lease, -which expires after an amount of time chosen by the administrator (by -default, one day). Before leases expire, the clients to which leases -are assigned are expected to renew them in order to continue to use -the addresses. Once a lease has expired, the client to which that -lease was assigned is no longer permitted to use the leased IP -address. -.PP -In order to keep track of leases across system reboots and server -restarts, dhcpd keeps a list of leases it has assigned in the -dhcpd.leases(5) file. Before dhcpd grants a lease to a host, it -records the lease in this file and makes sure that the contents of the -file are flushed to disk. This ensures that even in the event of a -system crash, dhcpd will not forget about a lease that it has -assigned. On startup, after reading the dhcpd.conf file, dhcpd -reads the dhcpd.leases file to refresh its memory about what leases -have been assigned. -.PP -New leases are appended to the end of the dhcpd.leases -file. In order to prevent the file from becoming arbitrarily large, -from time to time dhcpd creates a new dhcpd.leases file from its -in-core lease database. Once this file has been written to disk, the -old file is renamed -.IR dhcpd.leases~ , -and the new file is renamed dhcpd.leases. If the system crashes in -the middle of this process, whichever dhcpd.leases file remains will -contain all the lease information, so there is no need for a special -crash recovery process. -.PP -BOOTP support is also provided by this server. Unlike DHCP, the BOOTP -protocol does not provide a protocol for recovering -dynamically-assigned addresses once they are no longer needed. It is -still possible to dynamically assign addresses to BOOTP clients, but -some administrative process for reclaiming addresses is required. By -default, leases are granted to BOOTP clients in perpetuity, although -the network administrator may set an earlier cutoff date or a shorter -lease length for BOOTP leases if that makes sense. -.PP -BOOTP clients may also be served in the old standard way, which is to -simply provide a declaration in the dhcpd.conf file for each -BOOTP client, permanently assigning an address to each client. -.PP -Whenever changes are made to the dhcpd.conf file, dhcpd must be -restarted. To restart dhcpd, send a SIGTERM (signal 15) to the -process ID contained in -.IR RUNDIR/dhcpd.pid , -and then re-invoke dhcpd. Because the DHCP server database is not as -lightweight as a BOOTP database, dhcpd does not automatically restart -itself when it sees a change to the dhcpd.conf file. -.SH COMMAND LINE -.PP -The names of the network interfaces on which dhcpd should listen for -broadcasts may be specified on the command line. This should be done -on systems where dhcpd is unable to identify non-broadcast interfaces, -but should not be required on other systems. If no interface names -are specified on the command line dhcpd will identify all network -interfaces which are up, elimininating non-broadcast interfaces if -possible, and listen for DHCP broadcasts on each interface. -.PP -If dhcpd should listen on a port other than the standard (port 67), -the -.B -p -flag may used. It should be followed by the udp port number on which -dhcpd should listen. This is mostly useful for debugging purposes. -.PP -To run dhcpd as a foreground process, rather than allowing it to run -as a daemon in the background, the -.B -f -flag should be specified. This is useful when running dhcpd under a -debugger, or when running it out of inittab on System V systems. -.PP -To have dhcpd log to the standard error descriptor, specify the -.B -d -flag. This can be useful for debugging, and also at sites where a -complete log of all dhcp activity must be kept but syslogd is not -reliable or otherwise cannot be used. Normally, dhcpd will log all -output using the syslog(3) function with the log facility set to -LOG_DAEMON. -.PP -Dhcpd can be made to use an alternate configuration file with the -.B -cf -flag, or an alternate lease file with the -.B -lf -flag. Because of the importance of using the same lease database at -all times when running dhcpd in production, these options should be -used \fBonly\fR for testing lease files or database files in a -non-production environment. -.SH CONFIGURATION -The syntax of the dhcpd.conf(8) file is discussed seperately. This -section should be used as an overview of the configuration process, -and the dhcpd.conf(8) documentation should be consulted for detailed -reference information. -.PP -.SH Subnets -dhcpd needs to know the subnet numbers and netmasks of all subnets for -which it will be providing service. In addition, in order to -dynamically allocate addresses, it must be assigned one or more ranges -of addresses on each subnet which it can in turn assign to client -hosts as they boot. Thus, a very simple configuration providing DHCP -support might look like this: -.nf -.sp 1 - subnet 239.252.197.0 netmask 255.255.255.0 { - range 239.252.197.10 239.252.197.250; - } -.fi -.PP -Multiple address ranges may be specified like this: -.nf -.sp 1 - subnet 239.252.197.0 netmask 255.255.255.0 { - range 239.252.197.10 239.252.197.107; - range 239.252.197.113 239.252.197.250; - } -.fi -.PP -If a subnet will only be provided with BOOTP service and no dynamic -address assignment, the range clause can be left out entirely, but the -subnet statement must appear. -.PP -.SH Lease Lengths -DHCP leases can be assigned almost any length from zero seconds to -infinity. What lease length makes sense for any given subnet, or for -any given installation, will vary depending on the kinds of hosts -being served. -.PP -For example, in an office environment where systems are added from -time to time and removed from time to time, but move relatively -infrequently, it might make sense to allow lease times of a month of -more. In a final test environment on a manufacturing floor, it may -make more sense to assign a maximum lease length of 30 minutes - -enough time to go through a simple test procedure on a network -appliance before packaging it up for delivery. -.PP -It is possible to specify two lease lengths: the default length that -will be assigned if a client doesn't ask for any particular lease -length, and a maximum lease length. These are specified as clauses -to the subnet command: -.nf -.sp 1 - subnet 239.252.197.0 netmask 255.255.255.0 { - range 239.252.197.10 239.252.197.107; - default-lease-time 600; - max-lease-time 7200; - | -.fi -.PP -This particular subnet declaration specifies a default lease time of -600 seconds (ten minutes), and a maximum lease time of 7200 seconds -(two hours). Other common values would be 86400 (one day), 604800 -(one week) and 2592000 (30 days). -.PP -Each subnet need not have the same lease\(emin the case of an office -environment and a manufacturing environment served by the same DHCP -server, it might make sense to have widely disparate values for -default and maximum lease times on each subnet. -.SH BOOTP Support -Each BOOTP client must be explicitly declared in the dhcpd.conf -file. A very basic client declaration will specify the client -network interface's hardware address and the IP address to assign to -that client. If the client needs to be able to load a boot file from -the server, that file's name must be specified. A simple bootp -client declaration might look like this: -.nf -.sp 1 - host haagen { - hardware ethernet 08:00:2b:4c:59:23; - fixed-address 239.252.197.9; - filename "/tftpboot/haagen.boot"; - } -.fi -.SH Options -DHCP (and also BOOTP with Vendor Extensions) provide a mechanism -whereby the server can provide the client with information about how -to configure its network interface (e.g., subnet mask), and also how -the client can access various network services (e.g., DNS, IP routers, -and so on). -.PP -These options can be specified on a per-subnet basis, and, for BOOTP -clients, also on a per-client basis. In the event that a BOOTP -client declaration specifies options that are also specified in its -subnet declaration, the options specified in the client declaration -take precedence. An reasonably complete DHCP configuration might -look something like this: -.nf -.sp 1 - subnet 239.252.197.0 netmask 255.255.255.0 { - range 239.252.197.10 239.252.197.250; - default-lease-time 600 max-lease-time 7200; - option subnet-mask 255.255.255.0; - option broadcast-address 239.252.197.255; - option routers 239.252.197.1; - option domain-name-servers 239.252.197.2, 239.252.197.3; - option domain-name "isc.org"; - } -.fi -.PP -A bootp host on that subnet that needs to be in a different domain and -use a different name server might be declared as follows: -.nf -.sp 1 - host haagen hardware ethernet 08:00:2b:4c:59:23 { - fixed-address 239.252.197.9; - filename "/tftpboot/haagen.boot"; - option domain-name-servers 192.5.5.1; - option domain-name "vix.com"; - } -.fi -.PP -A more complete description of the dhcpd.conf file syntax is provided -in dhcpd.conf(5). -.SH FILES -.B ETCDIR/dhcpd.conf, DBDIR/dhcpd.leases, RUNDIR/dhcpd.pid, -.B DBDIR/dhcpd.leases~. -.SH SEE ALSO -dhcpd.conf(5), dhcpd.leases(5) -.SH AUTHOR -.B dhcpd(8) -was written by Ted Lemon <mellon@vix.com> -under a contract with Vixie Labs. Funding -for this project was provided by the Internet Software Corporation. -Information about the Internet Software Consortium can be found at -.B http://www.isc.org/isc. |