[ 9 May 1998
  The Linux DHCPcd 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. ]


                     How to setup Linux as DHCP client
     _________________________________________________________________
   
   Disclaimer: The information contained herein is NOT official
   information of any kind and there are no warranties to the accuracy of
   the data. All information is provided in good faith. Use at your own
   risk.
     _________________________________________________________________
   
   Vladimir Vuksan, vuksan@veus.hr
   $Revision: 1.5 $ $Date: 1998/04/21 12:21:11 $
   
  Introduction
  
   This HOWTO explains how to setup your Linux system to work in a DHCP
   environment as a client (DHCPcd). If you are looking for a DHCP server
   you need to read DHCPd mini-HOWTO at
   http://sunsite.unc.edu/LDP/HOWTO/mini/DHCPd. DHCP stands for Dynamic
   Host Configuration Protocol. It is a protocol that allows a client
   machine to obtain network information from a server. Many
   organizations are starting to use it because it eases network
   administration especially on large networks or networks which have
   lots of mobile users. DHCP is also being heavily used by cable
   Internet service provider such as MediaOne Express, Time Warner etc.
   More info about DHCP can be found in DHCP FAQ.
   
  Road Runner Service
  
   If you have Road Runner cable service check out
   http://people.qualcomm.com/karn/rr/index.html. If that doesn't solve
   your problem try following.
   
  2.1.x kernels
  
   If you are running a > 2.1.30 kernel (don't remember the exact number
   and www.linuxhq.com is down currently) you might encounter a problem
   with the dhcpc. According to Dan Khabaza:
   "The changes are due to differences in ipv4 network package, in the
   way it sets the defaults for several fields."
   
   Dan has provided a patch for it that can be obtained at
   http://www.cro.net/~vuksan/dhcppatch. To apply it just copy it to the
   dhcpcd source directory (instruction how to get source are in the
   following section) and type
   
patch < dhcppatch

   dhcpcd should compile cleanly after the patch has been applied. Note
   that this patch works only against dhcpcd 0.65 :-(.
   
   Another patch has been provided by Paul Rossington if you have
   problems with the one above. It is actually the whole if.C file. Get
   it at http://www.cro.net/~vuksan/if.C and copy it to the dhcpcd source
   directory.
   
   Other alternative when running 2.1.x kernels is to use dhcpcd 1.3.3
   which is a modified version that has been written by Sergei Viznyuk
   sergei@phystech.com in order to avoid problems with 2.1.x kernels. You
   can fetch it at:
   
   http://www.cps.msu.edu/~dunham/out/dhcpcd-1.3.3.tar.gz
   
  RedHat 5.0 users
  
   DHCPcd configuration under RedHat 5.0 is really easy. All you need to
   do is start the Control Panel by typing
   
control-panel

   Then select "Network Configuration" and under eth0 interface define
   DHCP as your protocol. Other parameters should be left blank.
   
  Token Ring network
  
   If you are trying to run dhcpcd on the Token Ring Network it will not
   work. This is the solution provided to me by Henrik Stoerner:
   
   The problem is that dhcpcd only knows about Ethernet cards. If it
   finds a Token-Ring card, it refuses to do anything with it and reports
   "interface is not ethernet". 
   
   The solution is to apply a simple patch to the dhcpcd-0.65 sources. I
   have put up a small web page with the patch, RedHat RPM-files and a
   precompiled binary at http://eolicom.olicom.dk/~storner/dhcp/
   
   The patch has been sent to the dhcpcd maintainer, so hopefully it will
   be included in a future release of dhcpcd.
   
  Method
  
   Step 1) 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. The
   description of the package reads:
Title:          dhcpcd
Version:        0.70
Entered-date:   05NOV97
Description:    dhcpcd is an RFC2131 compliant DHCP client daemon. It
                gets an IP address and other information from a
                corresponding DHCP server, configures the network
                interface automatically, and tries to renew the lease
                time according to RFC2131. It works in the RFC1541
                compliant mode when the '-r' option is specified.
                So far it is found that dhcpcd 0.70 works with the
                following DHCP servers:
                  1. ISC's dhcpcd-BETA-5.15
                  2. DHCP server on Windows NT server 3.51
                  3. DHCP server version 1.3b by WIDE project.
                  4. DHCP server in the SolarNet PC-Admin 1.5 package
                  5. DHCP server used in Time Warner Cable's
                     Internet Access Service
                  6. DHCP server used in Bell Atlantic ADSL
                See the "Changes" file if you want to know the difference
                from the previous version.
Keywords:       DHCP, client, Linux
Author:         yoichi@fore.com (Yoichi Hariguchi)
Maintained-by:  yoichi@fore.com (Yoichi Hariguchi)
Primary-site:   ftp.kobe-u.ac.jp /pub/PC-UNIX/Linux/network/dhcp
                33kB dhcpcd-0.70.tar.gz
Alternate-site: sunsite.unc.edu /pub/Linux/system/Network/daemons
                33kB dhcpcd-0.70.tar.gz
Original-site:
Platforms:       Linux 1.2.xx, 1.3.xx, 2.0.x
Copying-policy: GPL

  Slackware
  
   You can download the latest copy of the DHCPcd from any sunsite mirror
   or following:
   
     ftp://ftp.cdrom.com/pub/linux/sunsite/system/network/daemons/.
   
     ftp://sunsite.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
cd dhcpcd-0.70

make

     You need to be root to do the following
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. Now
   skip to Step 2
   
  RedHat
  
   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://tsx-11.mit.edu/pub/linux/distributions/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 part. When done go to Step 2
   
  Debian
  
   There is deb package of DHCPcd at
   
     ftp://ftp.debian.org/debian/stable/binary/net/
   
   or you can follow the Slackware installation instructions.
   
   In order to unpack the deb package type
dpkg -i /where/ever/your/debian/packages/are/dhcpd*deb

   When done go to Step 2
     _________________________________________________________________
   
   Step 2)
   
   Following step(s) are depended on your needs.
   
   a) If you need network connectivity only occasionally you can start
   dhcpcd from the command line (you need to be root to execute it) by
   typing
   
/usr/sbin/dhcpcd

   When you need to down (turn off) the network type
/usr/sbin/dhcpcd -k

   You now only lack nameservers configuration file (/etc/resolv.conf).
   For instructions on how to create a resolv.conf go to Step 3
   
   b) If you want (need) network connectivity all the time and would like
   dhcpcd to start at boot time follow the steps below.
   
  Slackware
  
   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. It should look
   as follows:
#!/bin/sh
#
# rc.inet1      This shell script boots up the base INET system.
#
# Version:      @(#)/etc/rc.d/rc.inet1  1.01    05/27/93
#

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 the above file as rc.inet1. Reboot your computer. Go to Step 3.
   
  RedHat
  
   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 and go to Step 3
   
  Debian
  
   It appears that there isn't a need for any DHCPcd configuration
   because:
From: Heiko Schlittermann

     The dhcpcd package installs it's startup script as usual for debian
   packages in /etc/init.d/, 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

   Go to Step 3.
     _________________________________________________________________
   
   Step 3) This step should be the same for all distributions.
   
   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. 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 to the syslog (on
   Slackware /var/adm/syslog) if you need to check up on it.
   
   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 :-).
   
  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
   
   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
   from Step 2) ie. instead of
/sbin/dhcpcd

   you will have
/sbin/dhcpcd -r

   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
   acurately :-). You are missing the ! (bang) in one of the if
   statements Jump back up and read it again.
   
   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) which 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. 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.
     _________________________________________________________________
   
   Thanks to all the people that contributed with their ideas and
   suggestions. Especially the following:
   
   Heiko Schlittermann (heiko@os.inf.tu-dresden.de)
   Jonathan Smith (jps2@ra.msstate.edu)
   Dan Khabaza (danyh@iil.intel.com)
   Hal Sadofsky (sadofsky@math.uoregon.edu)
   Henrik Stoerner (henrik_stoernet@olicom.dk)
   Paul Rossington (paulrossington@unn.unisys.com)
