  DHCP mini-HOWTO (DHCPd/DHCPcd)
  Vladimir Vuksan, vuksan@veus.hr
  v4.4, 11 September 1999

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

  Table of Contents


  1. Introduction

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

  2. DHCP protocol

  3. Client Setup

     3.1 Downloading the client daemon (dhcpcd)
     3.2 Slackware
     3.3 RedHat 6.x and Mandrake 6.x
     3.4 RedHat 5.x
     3.5 RedHat 4.x and Caldera OpenLinux 1.1/1.2
     3.6 Debian
     3.7 LinuxPPC and MkLinux
     3.8 Tying it all together
     3.9 Various notes
     3.10 Troubleshooting

  4. DHCP Server Setup

     4.1 DHCP server for UNIX
     4.2 DHCP server configuration
     4.3 Options for DHCPd
     4.4 Starting the server


  ______________________________________________________________________



  1.  Introduction




  1.1.  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.  Much content
  in this document are assumptions, which appear to work for people. Use
  the information at your own risk.



  1.2.  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://metalab.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://www.linuxdoc.org/>



  Following translations of the DHCP mini-HOWTO are available:




  ·  Chinese -  <http://www.linux.org.tw/CLDP/mini/DHCP.html>

  ·  Japanese -  <http://www.linux.or.jp/JF/JFdocs/DHCP.html>


  Permission is hereby granted to all individuals who want to translate
  the document into their own language. I would only ask that you
  provide a link back to this document and inform me of a URL to your
  translation so I can include a link to it.



  1.3.  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.



  1.4.  Contributors

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

  The following people have contributed to this mini-HOWTO.

  ·  Heiko Schlittermann

  ·  Jonathan Smith

  ·  Dan Khabaza

  ·  Hal Sadofsky

  ·  Henrik Stoerner

  ·  Paul Rossington



  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 the Linux HOWTO coordinator
     at

     linux-howto@metalab.unc.edu <mailto:linux-howto@metalab.unc.edu>




  2.  DHCP protocol


  DHCP is Dynamic Host Configuration Protocol. It is used to control
  vital networking parameters of hosts (running clients) with the help
  of a 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 <http://web.syr.edu/~jmwobus/comfaqs/dhcp.faq.html>.


  This mini-HOWTO covers both the DHCP _SERVER_ daemon as well as DHCP
  _CLIENT_ daemon. Most people need the client daemon which is used by
  workstations to obtain network information from a remote server. The
  server daemon is used by system administrators to distribute network
  information to clients so if you are just a regular user you need the
  _CLIENT_ daemon.


  3.  Client Setup


  Currently there are three different DHCP client programs for Linux,
  dhcpcd, pump and dhclient. This mini-HOWTO deals with dhcpcd.


  3.1.  Downloading the client daemon (dhcpcd)


  2.0.x kernels


  No matter what distribution you are using you will need to download
  the DHCP client daemon for Linux. The package you need to download is
  called dhcpcd and the current version is 0.70. You can read the
  description of the package here
  <ftp://metalab.unc.edu/pub/Linux/system/network/daemons/dhcpcd-0.70.lsm>.



  2.2.x kernels



  Due to changes in ipv4 network package in 2.1.x and 2.2.x kernels
  (e.g. way it sets the  defaults for several fields) dhcpcd doesn't
  work properly. Unless you are using RedHat 6.x (which comes with
  dhcpcd 1.3.x and 2.2.x kernel) you will need to download an
  alternative version of dhcpcd (1.3.x)  which is a modified version
  that has been written by Sergei Viznyuk  sergei@phystech.com in order
  to avoid mentioned problems. dhcpcd 1.3.x should work under 2.0.x
  kernels as well. You can download it at:




  ·  <ftp://phystech.dyn.ml.org/pub/>

  ·  <http://www.cps.msu.edu/~dunham/out/dhcpcd-1.3.6.tar.gz>



  Then follow the instructions below. They should be the same.


  3.2.  Slackware


  You can download the latest copy of the DHCPcd from any Metalab mirror
  or following:


  ·  <ftp://ftp.cdrom.com/pub/linux/metalab/system/network/daemons/>

  ·  <ftp://metalab.unc.edu/pub/Linux/system/network/daemons>

  ·  <ftp://ftp.kobe-u.ac.jp/pub/PC-UNIX/Linux/network/dhcp> (Primary
     site in Japan)



  Download the latest version of dhcpcd.tar.gz


  ·  Unpack it



     tar -zxvf dhcpcd-0.70.tar.gz


  ·  cd into the directory and make dhcpcd


     cd dhcpcd-0.70

     make


  ·  Install it (you have to run the following command as root)


     make install


  This will create the directory /etc/dhcpc where DHCPcd will store the
  DHCP information and dhcpcd file will be copied into /usr/sbin.

  In order to make the system initialize using DHCP during boot type:

  cd /etc/rc.d

  mv rc.inet1 rc.inet1.OLD


  This will move the old network initialization script into
  rc.inet1.OLD.  You now need to create the new rc.inet1 script.
  Following code is all you need:


  ______________________________________________________________________
  #!/bin/sh
  #
  # rc.inet1      This shell script boots up the base INET system.

  HOSTNAME=`cat /etc/HOSTNAME` #This is probably not necessary but I
                               #will leave it in anyways

  # Attach the loopback device.
  /sbin/ifconfig lo 127.0.0.1
  /sbin/route add -net 127.0.0.0 netmask 255.0.0.0 lo

  # IF YOU HAVE AN ETHERNET CONNECTION, use these lines below to configure the
  # eth0 interface. If you're only using loopback or SLIP, don't include the
  # rest of the lines in this file.

  /usr/sbin/dhcpcd
  ______________________________________________________________________



  Save it and reboot your computer.



  When you are finished go the ``last step''


  3.3.  RedHat 6.x and Mandrake 6.x


  DHCPcd configuration under RedHat 6.0+ is really easy. All you need to
  do is start the Control Panel by typing



  control-panel




  ·  Select "Network Configuration"

  ·  Click on Interfaces

  ·  Click Add

  ·  Select Ethernet

  ·  In the Edit Ethernet/Bus Interface select "Activate interface at
     boot time" as well as select DHCP as Interface configuration
     protocol




  Please note that in RedHat 6.x Redhat as default includes a DHCP
  client called pump instead of above mentioned dhcpcd. CD-ROM does
  include dhcpcd RPM so if you have no luck with pump install dhcpcd and
  then try to follow installation instructions for Redhat 5.x



  Additional notes from Alexander Stevenson
  <mailto:alexander.stevenson@home.com>:



  I had no luck with DHCPcd. What finally worked for me was "pump",
  which comes with Linux Mandrake 6.0 (and so I assume it is included
  with RedHat as well). The command I used was:



  pump -i eth0 -h hostname



  It didn't matter what "hostname" was, but without it the server would
  not respond.



  I then changed the line in my /sbin/ifup script to reflect the change;
  the default version does not have the -h switch, and so didn't work
  for me.



  Basically, if you're using linuxconf, and after setting the adapter to
  "DHCP" it still doesn't work, try adding a "-h hostname" to the pump
  line in the /sbin/ifup script. My script now looks like this:


  ______________________________________________________________________
  ...
  if [ -n "$PUMP" ]; then
      echo -n "Determining IP information for $DEVICE..."
      if /sbin/pump -i $DEVICE -h hostname; then
          echo " done."
      else
          echo " failed."
          exit 1
      fi
  else ...
  ______________________________________________________________________





  That is it. Reboot your machine or type



  /sbin/ifup eth0



  On the command line.


  3.4.  RedHat 5.x


  DHCPcd configuration under RedHat 5.0+ is really easy. All you need to
  do is start the Control Panel by typing



  control-panel




  ·  Select "Network Configuration"

  ·  Click on Interfaces

  ·  Click Add

  ·  Select Ethernet

  ·  In the Edit Ethernet/Bus Interface select "Activate interface at
     boot time" as well as select DHCP as Interface configuration
     protocol



  When you are finished go the ``last step''



  3.5.  RedHat 4.x and Caldera OpenLinux 1.1/1.2


  DHCPcd is included in the standard RedHat distribution as an RPM and
  you can find it on your distribution's CD-ROM in RPMS directory or you
  can download it from:


  <ftp://ftp.redhat.com/pub/redhat/redhat-4.2/i386/RedHat/RPMS/dhcpcd-0.6-2.i386.rpm>



  and install it with

  rpm -i dhcpcd-0.6-2.i386.rpm



  Alternatively you can compile your own version by following the steps
  outlined in the ``Slackware''.



  This information was provided to me by nothing nothing@cc.gatech.edu











  ______________________________________________________________________
  Removed my static ip and name from /etc/resolv.conf. However, I
  did leave in the search line and my two nameserver lines (for some reason my
  dhcpcd never creates a /etc/dhcpc/resolv.conf, so I have to use a static
  /etc/resolv.conf).

  In /etc/sysconfig/network I removed the HOSTNAME and GATEWAY
  entries. I left the other entries as is
  (NETWORKING, DOMAINNAME, GATEWAYDEV).

  In /etc/sysconfig/network-scripts/ifcfg-eth0 I removed the IPADDR,
  NETMASK, NETWORK, and BROADCAST entries. I left DEVICE and ONBOOT as is.
  I changed the BOOTPROTO line to BOOTPROTO=dhcp.

  Save the file. Reboot your computer.
  ______________________________________________________________________



  When you are finished go the ``last step''



  3.6.  Debian


  There is a deb package of DHCPcd at



   <ftp://ftp.debian.org/debian/dists/slink/main/binary-
  i386/net/dhcpcd_0.70-4.deb>

  or you can follow the Slackware installation instructions.  To unpack
  the deb package type

  dpkg -i /where/ever/your/debian/packages/are/dhcpd*deb



  It appears that there isn't a need for any DHCPcd configuration
  because:

  From: Heiko Schlittermann (heiko@os.inf.tu-dresden.de)



  The dhcpcd package installs it's startup script as usual for debian
  packages in /etc/init.d/<package_name>, here as /etc/init.d/dhcpcd,
  and links this to the various /etc/rc?.d/ directories.



  The contents of the /etc/rc?.d/ dirs is then executed at boot time.



  If you don't reboot after installing you should consider starting the
  daemon manually:


  /etc/init.d/dhcpcd start


  When you are finished go the ``last step''

  3.7.  LinuxPPC and MkLinux


  Following section has been written by R. Shapiro



  As of the "1999" (R5) release, Linuxppc is now almost completely
  compatible with Redhat 6, with one caveat (see below).  In general the
  instructions are exactly the same as for the current release of
  ``Redhat 6.x''.



  The remaining problem is that Redhat 6 uses the 'pump' client for dhcp
  by default, and 'pump' doesn't work reliably in Linuxppc.  To get
  around this, you should install the latest dhcpcd from Sergei Viznyuk,
  and then edit /sbin/ifup to use dhcpcd instead of pump. Change




  ______________________________________________________________________
  if [ "$BOOTPROTO" = bootp -o "$BOOTPROTO" = dhcp ]; then
       PUMP=true
   fi

   if [ -n "$PUMP" ]; then
  ______________________________________________________________________



  with


  ______________________________________________________________________
   if [  "$BOOTPROTO" = bootp ]; then
         echo " done."
       else
         echo " failed."
         exit 1
       fi
   elif [ "$BOOTPROTO" = dhcp ]; then
       echo -n "Determining IP information for $DEVICE..."
       if /sbin/dhcpcd -d $DEVICE ; then
         if [ -f /etc/dhcpc/dhcpcd-${DEVICE}.exe ]; then
             /etc/dhcpc/dhcpcd-${DEVICE}.exe
         fi
  ______________________________________________________________________





  and a coresponding changes for ifdown. Change


  ______________________________________________________________________
  if [ "$BOOTPROTO" = bootp -o "$BOOTPROTO" = dhcp ]; then
  ....
  fi
  ______________________________________________________________________




  with


  ______________________________________________________________________
  if [ "$BOOTPROTO" = bootp ]; then
  fi

  if [ "$BOOTPROTO" = dhcp ]; then
        if [ -f /var/run/dhcpcd-${DEVICE}.pid ]; then
                kill `cat /var/run/dhcpcd-${DEVICE}.pid`
                rm -f /var/run/dhcpcd-${DEVICE}.pid
        fi
  fi
  ______________________________________________________________________






  A working ppc rpm for dhcpcd is included on the Linuxppc 1999 cd; a
  slightly later rpm is available in the contrib directory on
  <ftp://ftp.linuxppc.org/>.  Sources, which compile out of the box in
  Linuxppc 1999, are available from



  <ftp://ftp.phystech.com/pub/dhcpcd-1.3.17-pl9.tar.gz>



  If you want a precompiled dhcpcd for linuxppc, send mail to


  3.8.  Tying it all together


  After your machine reboots your network interface should be
  configured.  Type:

  ifconfig

  You should get something like this


  ______________________________________________________________________
  lo        Link encap:Local Loopback
            inet addr:127.0.0.1  Bcast:127.255.255.255  Mask:255.0.0.0
            UP BROADCAST LOOPBACK RUNNING  MTU:3584  Metric:1
            RX packets:302 errors:0 dropped:0 overruns:0 frame:0
            TX packets:302 errors:0 dropped:0 overruns:0 carrier:0 coll:0

  eth0      Link encap:Ethernet  HWaddr 00:20:AF:EE:05:45
            inet addr:24.128.53.102  Bcast:24.128.53.255  Mask:255.255.254.0
            ^^^^^^^^^^^^^^^^^^^^^^^
            UP BROADCAST NOTRAILERS RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:24783 errors:1 dropped:1 overruns:0 frame:1
            TX packets:11598 errors:0 dropped:0 overruns:0 carrier:0 coll:96
            Interrupt:10 Base address:0x300
  ______________________________________________________________________






  If you have some normal number under inet. addr you are set. If you
  see 0.0.0.0 don't despair, it is a temporary setting before dhcpcd
  acquires the IP address. If even after few minutes you are seeing
  0.0.0.0 please check out  ``troubleshooting''.  DHCPcd is a daemon and
  will stay running as long as you have your machine on. Every three
  hours it will contact the DHCP server and try to renew the IP address
  lease. It will log all the messages in the syslog (on Slackware
  /var/adm/syslog, RedHat/OpenLinux /var/log/syslog).

  One final thing. You need to specify your nameservers. There are two
  ways to do it, you can either ask your provider to provide you with
  the addresses of your name server and then put those in the
  /etc/resolv.conf or DHCPcd will obtain the list from the DHCP server
  and will build a resolv.conf in /etc/dhcpc.  I decided to use DHCPcds
  resolv.conf by doing the following:


  Back up your old /etc/resolv.conf

  mv /etc/resolv.conf /etc/resolv.conf.OLD

  If directory /etc/dhcpc doesn't exist create it

  mkdir /etc/dhcpc

  Make a link from /etc/dhcpc/resolv.conf to /etc/resolv.conf

  ln -s /etc/dhcpc/resolv.conf /etc/resolv.conf


  If that doesn't work try this (fix suggested by nothing@cc.gatech.edu
  with a little amendment by Henrik Stoerner)




  This last step I had to perform only because my dhcpcd doesn't create
  an /etc/dhcpc/resolv.conf.  In /etc/sysconfig/network-scripts/ifup I
  made the following changes (which are a very poor hack, but they work
  for me):





  ______________________________________________________________________
  elif [ "$BOOTPROTO" = dhcp -a "$ISALIAS" = no ]; then
      echo -n "Using DHCP for ${DEVICE}... "
      /sbin/dhcpcd -c /etc/sysconfig/network-scripts/ifdhcpc-done ${DEVICE}
      echo "echo \$$ > /var/run/dhcp-wait-${DEVICE}.pid; exec sleep 30" | sh

      if [ -f /var/run/dhcp-wait-${DEVICE}.pid ]; then
          ^^^^
          echo "failed."
          exit 1
  ______________________________________________________________________



  I changed to:






  ______________________________________________________________________
  elif [ "$BOOTPROTO" = dhcp -a "$ISALIAS" = no ]; then
      echo -n "Using DHCP for ${DEVICE}... "
      /sbin/dhcpcd
      echo "echo \$$ > /var/run/dhcp-wait-${DEVICE}.pid; exec sleep 30" | sh

      if [ ! -f /var/run/dhcp-wait-${DEVICE}.pid ]; then
          ^^^^^^
         echo "failed."
         exit 1
  ______________________________________________________________________





  Notice the ! (bang) in if [ ! -f /var/run/dhcp-wait-${DEVICE}.pid ];





  Now sit back and enjoy :-).

  3.9.  Various notes


  Following step(s) are not necessary but might be useful to some people

  a)  If you need network connectivity only occasionally you can start
  dhcpcd from the command line (you have to be root to do this) with:


  /usr/sbin/dhcpcd

  When you need to down (turn off) the network type

  /usr/sbin/dhcpcd -k



  3.10.  Troubleshooting


  If you have followed the steps outlined above and you are unable to
  access the network there are several possible explanations:



  I. Your network card is not configured properly.


  During the boot up process your Linux will probe your network card and
  should say something along these lines:


  ______________________________________________________________________
  eth0: 3c509 at 0x300 tag 1, 10baseT port, address  00 20 af ee 11 11, IRQ 10.
  3c509.c:1.07 6/15/95 becker@cesdis.gsfc.nasa.gov
  ______________________________________________________________________



  If a message like this doesn't appear your ethernet card might not be
  recognized by your Linux system. If you have a generic ethernet card
  (a NE2000 clone) you should have received a disk with DOS utilities
  that you can use to set up the card. Try playing with IRQs until Linux
  recognizes your card (IRQ 9,10,12 are usually good).



  II. Your DHCP server supports RFC 1541/My DHCP server is Windows NT


  Try running dhcpcd by typing

  dhcpcd -r

  Use ifconfig to check if your network interface is configured (wait
  few seconds for the configuration process, initally it will say
  Inet.addr=0.0.0.0)

  If this solves your problem add the "-r" flag to the boot up scripts
  ie. instead of /sbin/dhcpcd you will have /sbin/dhcpcd -r



  For example under RedHat edit script /etc/sysconfig/network-
  scripts/ifup and change the following


  ______________________________________________________________________
          IFNAME=$[ {DEVICE} \
          "/sbin/dhcpcd -r -c /etc/"- etc etc.
  ______________________________________________________________________





  III. During bootup I get error message "Using DHCP for eth0 ...
  failed" but my system works fine.



  You are most likely using RedHat and you haven't followed instructions
  carefully :-). You are missing the ! (bang) in one of the if
  statements.  Jump ``here'' and check how to fix it.



  IV. My network works for few minutes and then stops responding



  There are some reports of gated (gateway daemon) screwing up routing
  on Linux boxes which results in problem described above. Check if
  gated is running



  ps -auxww | grep gate



  If it is try removing it with RedHat's RPM manager or removing the
  entry in /etc/rc.d/



  V. My ethernet card is recognized during boot up but I still get "NO
  DHCPOFFER" message in my logs. I also happen to have a PCMCIA ethernet
  card.



  You need to make sure that you have the 10BaseT port ("phone" plug) on
  your network card activated. Best way to verify it is to check what
  kind of connector your card is configured for during bootup e.g.


  ______________________________________________________________________
  eth0: 3c509 at 0x300 tag 1, 10baseT port, address  00 20 af ee 11 11, IRQ 10.
                              ^^^^^^^^^^^^
  3c509.c:1.07 6/15/95 becker@cesdis.gsfc.nasa.gov
  ______________________________________________________________________





  I have received reports of laptop users having this kind of problems
  due to the PCMCIA utilities (specifically ifport) that would set the
  connector type to 10Base2 (thinnet). You have to make sure you use
  10BaseT for your connection. If you are not reconfigure the card and
  restart the computer.



  VI. My DHCP client broadcasts requests but no one answers (Contributed
  by Peter Amstutz)



  On some systems, you need to include some hostname for your machine as
  part of the request.  With dhcpcd, do this with 'dhcpcd -h foohost'
  Probably the hostname wanted will be your account username on the
  network.



  VII. I have followed all the steps but still my machine is not able to
  connect



  The cable modem will usually memorize the ethernet address of your
  network card so if you connect a new computer or switch network cards
  you will somehow have to "teach" your cable modem to recognize the new
  computer/card. Usually you can turn of the modem and bring it back up
  while computer is on or you will have to call tech support and tell
  them that you have changed a network card in the computer.



  You have firewall rules (ipfwadm rules) that disallow port 67/68
  traffic used by DHCP to distribute configuration info. Check your
  firewall rules carefully.



  VIII. I have MediaOne Express service and I still can't connect.



  It appears that MediaOne has been using adding some things to DHCP
  that shouldn't be there. Supposedly this is not a problem anymore but
  if you experience outages check for these things. If you are (un)lucky
  to have Windows NT on your machine if you go into Event Viewer you
  will see a warning like this.


  DHCP received an unknown option 067 of length 005. The raw option data
  is given  below.

  0000: 62 61 73 69 63            basic


  If this is the problem go to <ftp://vanbuer.ddns.org/pub/> and either
  download a binary or get the source for the change.




  4.  DHCP Server Setup

  4.1.  DHCP server for UNIX

  There are several DHCP servers available for U*X-like OSes, both
  commercial and free. One of the more popular free DHCP servers is Paul
  Vixie/ISC DHCPd. Currently the latest version is 2.0 (suggested for
  most users) but 3.0 is in beta testing.  You can get them from

  <ftp://ftp.isc.org/isc/dhcp/>



  Some of the distributions provide binary packages for dhcpd so skip
  the following section if you got it installed that way.


  After you download unpack it. After you do cd into the distribution
  directory and type:

  ./configure

  It will take some time to configure the settings. After it is done
  type:

  make

  and

  make install




  4.2.  DHCP server configuration


  When done with installation type ifconfig -a. You should see something
  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. Quoted from DHCPd
  README:



  "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."



  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 255.255.255.0 dev eth0

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




  4.3.  Options for DHCPd


  Now you need to configure DHCPd. In order to do this you will have to
  create or edit /etc/dhcpd.conf. There is a graphical interface for
  dhcpd configuration under KDE (  <http://www.kde.org/> ) called
  kcmdhcpd that is very similar to the DHCP configurator on Windows NT.
  When KDE 2.0 comes out it should come with kcmdhcpd or you could get
  it directly from:



  <ftp://ftp.us.kde.org/pub/kde/unstable/apps/network/>



  If you want to configure it by hand follow instructions below.



  Most commonly what you want to do is assign IP addresses randomly.
  This can be done with settings as follows:




  ______________________________________________________________________
  # Sample /etc/dhcpd.conf
  # (add your comments here)
  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 192.168.1.10-192.168.1.100 or 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 (allowed) lease will be
  7200 seconds. The server will also "advise" the client that it should
  use 255.255.255.0 as its subnet mask,  192.168.1.255 as its broadcast
  address, 192.168.1.254 as the router/gateway and 192.168.1.1 and
  192.168.1.2 as its DNS servers.



  If you need to specify a WINS server for your Windows clients you will
  need to include the netbios-name-servers option e.g.


  ______________________________________________________________________
  option netbios-name-servers 192.168.1.1;
  ______________________________________________________________________





  You can also assign specific IP addresses based on 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 192.168.1.222 to a client with ethernet
  address 08:00:2b:4c:59:23.



  You can also mix and match e.g. you can have certain clients getting
  "static" IP addresses (e.g. servers) and others being alloted dynamic
  IPs (e.g. mobile users with laptops). There are a number of other
  options e.g. nis server addresses, time server addresses etc., if you
  need any of those options please read the dhcpd.conf man page.




  4.4.  Starting the server


  There is only one thing to do before starting the server. In most
  cases DHCP installation doesn't create a dhcpd.leases files. This file
  is used by DHCPd to store information about current leases. It is in
  the plain text form so you can view it during the operation of DHCPd.
  To create dhcpd.leases type

  touch /var/state/dhcp/dhcpd.leases

  on the command line. This will create an empty file (file size = 0).
  Some of the older version of dhcpd 2.0 placed the file in
  /etc/dhcpd.leases.  You do not need to make any changes to it it
  should be empty.  If you get a message saying that file exists simply
  ignore it and go to the next step.


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

  /usr/sbin/dhcpd


  This will invoke dhcpd on eth0 device. If you want to invoke it on
  another device simply supply it on the command line e.g.

  /usr/sbin/dhcpd eth1

  To verify that everything is working fine you should first turn on the
  debugging mode and put the server in foreground. You can do this by
  typing

  /usr/sbin/dhcpd -d -f

  Then boot up one of your clients and check out the console of your
  server.  You will see a number of debugging messages come up. If
  everything works out fine you are done :-).





































































