[ 9 May 1998
  The Linux DHCPd mini-HOWTO is no longer being maintained.  The DHCPd and
  DHCPcd have been merged into a single mini-HOWTO called DHCP.  Please
  feel free to contact me at <linux-howto@sunsite.unc.edu> if you have any
  questions or concerns. ]

  DHCP server mini-HOWTO (DHCPd)
  Vladimir Vuksan, vuksan@veus.hr
  v1.3, 15 March 1998

  This document attempts to answer basic questions on how to setup your
  Linux box to serve as a DHCP server.
  ______________________________________________________________________

  Table of Contents


  1. Introduction

     1.1 New Versions of this Document
     1.2 Feedback
     1.3 Contributors
     1.4 Standard Disclaimer
     1.5 Copyright Information

  2. Setup

     2.1 Introduction
     2.2 DHCPD server for Linux.
     2.3 Network Configuration.
     2.4 Options for DHCPd
     2.5 Running the server


  ______________________________________________________________________



  1.  Introduction





  1.1.  New Versions of this Document

  New versions of this document will be periodically posted to
  comp.os.linux.answers.  They will also be added to the various
  anonymous FTP sites who archive such information, including:

  ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO

  In addition, you should generally be able to find this document on the
  Linux Documentation Project page via:

  http://sunsite.unc.edu/LDP/


  1.2.  Feedback

  Feedback is most certaintly welcome for this document.  Without your
  submissions and input, this document wouldn't exist. So, please post
  your additions, comments and criticisms to vuksan@veus.hr.



  1.3.  Contributors

  This document has been modified from the original version by Paul
  Makeev.


  1.4.  Standard Disclaimer

  No liability for the contents of this documents can be accepted.  Use
  the concepts, examples and other content at your own risk.  As this is
  a new edition of this document, there may be errors and inaccuracies,
  that may of course be damaging to your system.  Proceed with caution,
  and although this is highly unlikely, I don't take any responsibility
  for that.

  Also bear in mind that this is NOT official information.  Obtaining
  official information is usually an impossibility with many ISPs. Much
  content in this document are assumptions, which appear to work for
  people. Use the information at your own risk.


  1.5.  Copyright Information

  This document is copyrighted (c)1998 Vladimir Vuksan and distributed
  under the following terms:



  ·  Linux HOWTO documents may be reproduced and distributed in whole or
     in part, in any medium physical or electronic, as long as this
     copyright notice is retained on all copies. Commercial
     redistribution is allowed and encouraged; however, the author would
     like to be notified of any such distributions.

  ·  All translations, derivative works, or aggregate works
     incorporating any Linux HOWTO documents must be covered under this
     copyright notice.  That is, you may not produce a derivative work
     from a HOWTO and impose additional restrictions on its
     distribution. Exceptions to these rules may be granted under
     certain conditions; please contact the Linux HOWTO coordinator at
     the address given below.

  ·  If you have questions, please contact Greg Hankins, the Linux HOWTO
     coordinator, at

     tjbynum@metalab.unc.edu





  2.  Setup

  2.1.  Introduction


  DHCP is Dynamic Host Configuration Protocol. It is used to control
  vital networking parameters of hosts (running clients) with the help
  of server. DHCP is backward compatible with BOOTP. For more
  information see RFC 2131 (old RFC 1531) and other. (See Internet
  Resources section at the end of the document). You can also read DHCP
  FAQ.



  This mini-HOWTO is about DHCP _SERVER_ daemon. There is DHCP _client_
  daemon (DHCPcd) for Linux, which is not described here. Information
  about DHCPcd can be found at:

  http://sunsite.unc.edu/LDP/HOWTO/mini/DHCPcd.html


  2.2.  DHCPD server for Linux.

  There are several DHCP servers available for U*X-like OSes, both
  commercial and free. One of more popular free DHCP servers is Paul
  Vixie/ISC DHCPd. You can get it from

  ftp://ftp.isc.org/isc/dhcp/dhcp-1.0.0.tar.gz



  After you do you need to unpack. It will create a directory of its
  own. Go into it and type



  ./configure



  It will take few seconds to configure the settings. Then type:



  make



  and



  make install




  2.3.  Network Configuration.


  When done with installation type ifconfig -a. You should get output
  like this:



  eth0      Link encap:10Mbps Ethernet  HWaddr 00:C0:4F:D3:C4:62 inet
  addr:183.217.19.43  Bcast:183.217.19.255  Mask:255.255.255.0 UP
  BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1 RX packets:2875542
  errors:0 dropped:0 overruns:0 TX packets:218647 errors:0 dropped:0
  overruns:0 Interrupt:11 Base address:0x210



  If it doesn't say MULTICAST you should reconfigure your kernel and add
  multicast support. On most systems you will not need to do this.



  Next step is to add route for 255.255.255.255. README explains why:



  "In order for dhcpd to work correctly with picky DHCP clients (e.g.,
  Windows 95), it must be able to send packets with an IP destination
  address of 255.255.255.255.  Unfortunately, Linux insists on changing
  255.255.255.255 into the local subnet broadcast address (here, that's
  192.5.5.223).  This results in a DHCP protocol violation, and while
  many DHCP clients don't notice the problem, some (e.g., all Microsoft
  DHCP clients) do.  Clients that have this problem will appear not to
  see DHCPOFFER messages from the server."



  So you have to type



  route add -host 255.255.255.255 dev eth0



  If you get a message



  "255.255.255.255: Unknown host"



  You should try adding the following entry to your /etc/hosts file:



  255.255.255.255 all-ones



  Then, try:



  route add -host all-ones dev eth0



  or



  route add -net 255.255.255.0 dev eth0



  eth0 is of course the name of the network device you are using.  If it
  differs change it appropriately.




  2.4.  Options for DHCPd


  Now you need to configure DHCPd. In order to do this you will have to
  create or edit /etc/dhcpd.conf.



  Most commonly what you want to do is assign randomly IP addresses to
  clients on you local network. This can be done with a paragraphs like
  this



  ______________________________________________________________________
  default-lease-time 600;
  max-lease-time 7200;
  option subnet-mask 255.255.255.0;
  option broadcast-address 192.168.1.255;
  option routers 192.168.1.254;
  option domain-name-servers 192.168.1.1, 192.168.1.2;
  option domain-name "mydomain.org";

  subnet 192.168.1.0 netmask 255.255.255.0 {
     range 192.168.1.10 192.168.1.100;
     range 192.168.1.150 192.168.1.200;
  }
  ______________________________________________________________________





  This will result in DHCP server giving a client an IP address from the
  range of 192.168.1.10-192.168.1.100 and 192.168.1.150-192.168.1.200.
  It will lease an IP address for 600 seconds if the client doesn't ask
  for specific time frame. Otherwise the maximum lease it will allow is
  7200 seconds. The server will also advise the client that it should
  use 255.255.255.0 as its subnet mask, use 192.168.1.255 as its
  broadcast address, use 192.168.1.254 as the router/gateway and
  192.168.1.1 and 192.168.1.2 as its DNS servers.



  You can also assign specific IP addresses based upon clients ethernet
  address e.g.




  ______________________________________________________________________
  host haagen {
     hardware ethernet 08:00:2b:4c:59:23;
     fixed-address 192.168.1.222;
  }
  ______________________________________________________________________





  This will assign IP address of 192.168.1.222 to client with an
  ethernet address of 08:00:2b:4c:59:23.



  You can also mix and match e.g. you can have certain clients getting
  "static" IP addresses and others being alloted dynamic IPs. There are
  a number of other options, if you need any of them read the dhcpd.conf
  man page for details.




  2.5.  Running the server


  You can now invoke the DHCP server. Simply type (or include in the
  bootup scripts)

  /usr/sbin/dhcpd



  If you want to verify that everything is working fine you should first
  turn on the debugging mode and put the server in forground. You can do
  it by typing



  /usr/sbin/dhcpd -d -f



  Then try to obtain an IP address with a client. You will see a number
  of debugging messages coming out of the server.


















































