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diff --git a/server/dhcpd.8 b/server/dhcpd.8 deleted file mode 100644 index 18abfff8..00000000 --- a/server/dhcpd.8 +++ /dev/null @@ -1,266 +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''. -.Dd March 5, 1996 -.Dt dhcpd 8 -.Sh NAME -.Nm dhcpd -.Nd Dynamic Host Configuration Protocol server -.Sh SYNOPSIS -.Nm dhcpd -.Op Fl p port -.Sh DESCRIPTION -.Xr dhcpd 8 -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 but much more limited functionality. -.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 -.Xr dhcpd.conf 5 -file. -.Pp -On startup, dhcpd reads the -.Nm dhcpd.conf -file and keeps the list of available addresses on each subnet in -memory. When a host requests an address using the DHCP protocol, -dhcpd allocates an address for it. Each such host is assigned a -lease, which expires after an amount of time chosen by the -administrator (by default, one day). As leases expire, the hosts to -which they are assigned are expected to renew the leases if they wish -to continue to use the addresses. Once a lease has expired, the host -to which that lease is assigned is no longer permitted to use the IP -address assigned to it. -.Pp -In order to keep track of leases across system reboots and server -restarts, -.Nm dhcpd -keeps a list of leases it has assigned in the -.Xr 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, -.Nm dhcpd -will not forget about a lease that it has assigned. On startup, -after reading the -.Nm dhcpd.conf -file, -.Nm dhcpd -reads the -.Nm dhcpd.leases -file to refresh its memory about what leases have been assigned. -.Pp -New leases are appended to the end of the -.Nm dhcpd.leases -file. In order to prevent the file from becoming arbitrarily large, -from time to time -.Nm dhcpd -creates a new -.Nm dhcpd.leases -file from its in-core lease database. Once this file has been written -to disk, the old file is renamed -.Nm dhcpd.leases~ , -and the new file is renamed -.Nm dhcpd.leases . -If the system crashes in the middle of this process, -whichever -.Nm 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 requires that the server know the hardware address of -the client that is to be booted. The network administrator must -determine that address, allocate an IP address for the client, and -enter that information into the -.Nm dhcpd.conf -file. -.Pp -Whenever changes are made to the -.Nm dhcpd.conf -file, -.Nm dhcpd -must be restarted. To restart -.Nm dhcpd , -send a SIGTERM (signal 15) to the process ID contained in -.Nm /var/run/dhcpd.pid , -and then re-invoke -.Nm dhcpd . - -.Sh CONFIGURATION -The syntax of the -.Xr dhcpd.conf 8 -file is discussed seperately. This section should be used as an -overview of the configuration process, and the -.Xr dhcpd.conf 8 -documentation should be consulted for detailed reference information. -.Pp -.Sh Subnets -.Xr dhcpd 8 -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 -.Nm 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 complete list of DHCP Options and their syntaxes is provided in -.Xr dhcpd.conf 5 . -.Sh FILES -.Nm /etc/dhcpd.conf , -.Nm /etc/dhcpd.leases , -.Nm /var/run/dhcpd.pid , -.Nm /etc/dhcpd.leases~ . -.Sh SEE ALSO -.Xr dhcpd.conf 5 , -.Xr dhcpd.leases 5 -.Sh AUTHOR -.Xr dhcpd 8 -was written by Ted Lemon -.Nm <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 -.Nm http://www.isc.org/isc . |