[ 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 <[email protected]> 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, [email protected]
  $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
  [email protected] 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:         [email protected] (Yoichi Hariguchi)
Maintained-by:  [email protected] (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 ([email protected])

    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 [email protected]
  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 [email protected]

  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 [email protected]

  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 ([email protected])
  Jonathan Smith ([email protected])
  Dan Khabaza ([email protected])
  Hal Sadofsky ([email protected])
  Henrik Stoerner ([email protected])
  Paul Rossington ([email protected])

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