Chip 1998 September/CHIP Eylül 1998.iso/Slackwar/docs/mini/DHCPcd

Text File | 1997-03-16 | 14.7 KB | 716 lines

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, [e-mail]
   $Id: dhcp.html,v 1.2 1998/03/02 23:29:24 vuksan Exp $

  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 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 in 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




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
[e-mail] 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:         [e-mail] (Yoichi Hariguchi)
Maintained-by:  [e-mail] (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 ([e-mail])



 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 [e-mail] 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 [e-mail]


If a message like this doesn't appear your ethernet card might not be recognize
d
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 ba
ck 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/


  __________________________________________________________________________





Thanks to all the people that contributed with their ideas and
suggestions. Especially the following:



Heiko Schlittermann ([e-mail])

Jonathan Smith ([e-mail])

Dan Khabaza ([e-mail])

Hal Sadofsky ([e-mail])

Henrik Stoerner ([e-mail])

Paul Rossington ([e-mail])