357 lines
16 KiB
Plaintext
357 lines
16 KiB
Plaintext
Internet Software Consortium
|
|
Dynamic Host Configuration Protocol Distribution
|
|
Version 2, Beta 1, Patchlevel 21
|
|
March 29, 1998
|
|
|
|
Documentation for this software includes this README file, the
|
|
RELNOTES file, and the manual pages, which are in the server, common,
|
|
client and relay subdirectories. Internet standards relating to the
|
|
DHCP protocol are stored in the doc subdirectory. You will have the
|
|
best luck reading the manual pages if you build this software and then
|
|
install it, although you can read them directly out of the
|
|
distribution if you need to.
|
|
|
|
DHCP server documentation is in the dhcpd man page. Information about
|
|
the DHCP server lease database is in the dhcpd.leases man page.
|
|
Server configuration documentation is in the dhcpd.conf man page as
|
|
well as the dhcp-options man page. A sample DHCP server
|
|
configuration is in the file server/dhcpd.conf.
|
|
|
|
DHCP Client documentation is in the dhclient man page. DHCP client
|
|
configuration documentation is in the dhclient.conf man page and the
|
|
dhcp-options man page. The DHCP client configuration script is
|
|
documented in the dhclient-script man page. The format of the DHCP
|
|
client lease database is documented in the dhclient.leases man page.
|
|
|
|
DHCP relay agent documentation is in the dhcrelay man page.
|
|
|
|
To read installed manual pages, use the man command. Type "man page"
|
|
where page is the name of the manual page.
|
|
|
|
If you want to read manual pages that aren't installed, you can type
|
|
``nroff -man page |more'' where page is the filename of the
|
|
unformatted manual page. The filename of an unformatted manual page
|
|
is the name of the manual page, followed by '.', followed by some
|
|
number - 5 for documentation about files, and 8 for documentation
|
|
about programs.
|
|
|
|
If you do not have the nroff command, you can type ``more catpage''
|
|
where catpage is the filename of the catted man page. Catted man
|
|
pages names are the name of the manual page followed by ".cat"
|
|
followed by 5 or 8, as with unformatted manual pages.
|
|
|
|
Please note that until you install the manual pages, the pathnames of
|
|
files to which they refer will not be correct for your operating
|
|
system.
|
|
|
|
This is the first Beta release of Version 2 of the Internet Software
|
|
Consortium DHCP Distribution. In version 2.0, this distribution
|
|
includes a DHCP server, a DHCP client, and a BOOTP/DHCP relay agent.
|
|
This beta is believed to be fairly stable. However, DHCP server users
|
|
running a production environment should probably still use version
|
|
1.0, which is more stable, having been in a feature freeze since
|
|
November of 1996.
|
|
|
|
In this release, the server and relay agent currently work well on
|
|
NetBSD, Linux, FreeBSD, BSD/OS, Ultrix, Digital Alpha OSF/1, and SunOS
|
|
4.1.4. They can also be run usefully on Solaris as long as only one
|
|
broadcast network interface is configured. They also runs on QNX as
|
|
long as only one broadcast network interface is configured and a host
|
|
route is added from that interface to the 255.255.255.255 broadcast
|
|
address. If you are running a Linux 2.0.30 or previous kernel, the
|
|
DHCP daemons will only be able to operate on machines with a single
|
|
network interface.
|
|
|
|
The DHCP client currently only knows how to configure the network on
|
|
NetBSD, FreeBSD, BSD/os, Linux, Solaris and NextStep. The client
|
|
depends on a system-dependent shell script to do network
|
|
configuration - support for other operating systems is simply a matter
|
|
of porting this shell script to the new platform.
|
|
|
|
If you wish to run the DHCP Distribution on Linux, please see the
|
|
Linux-specific notes later in this document. If you wish to run on an
|
|
SCO release, please see the SCO-specific notes later in this document.
|
|
You particularly need to read these notes if you intend to support
|
|
Windows 95 clients. If you are running a version of FreeBSD prior to
|
|
2.2, please read the note on FreeBSD. If you are running HP-UX or
|
|
Ultrix, please read the notes for those operating systems below.
|
|
If you are running NeXTSTEP, please see the notes on NeXTSTEP below.
|
|
|
|
If you start dhcpd and get a message, "no free bpf", that means you
|
|
need to configure the Berkeley Packet Filter into your operating
|
|
system kernel. On NetBSD, FreeBSD and BSD/os, type ``man bpf'' for
|
|
information. On Digital Unix, type ``man pfilt''.
|
|
|
|
|
|
BUILDING THE DHCP DISTRIBUTION
|
|
|
|
To build the DHCP Distribution, unpack the compressed tar file using
|
|
the tar utility and the gzip command - type something like:
|
|
|
|
zcat dhcp-2.0b1pl21.tar.gz |tar xvf -
|
|
|
|
Now, cd to the dhcp-2.0b1pl21 subdirectory that you've just created and
|
|
configure the source tree by typing:
|
|
|
|
./configure
|
|
|
|
If the configure utility can figure out what sort of system you're
|
|
running on, it will create a custom Makefile for you for that
|
|
system; otherwise, it will complain. If it can't figure out what
|
|
system you are using, that system is not supported - you are on
|
|
your own.
|
|
|
|
Once you've run configure, just type ``make'', and after a while
|
|
you should have a dhcp server. If you get compile errors on one
|
|
of the supported systems mentioned earlier, please let us know.
|
|
If you get warnings, it's not likely to be a problem - the DHCP
|
|
server compiles completely warning-free on as many architectures
|
|
as we can manage, but there are a few for which this is difficult.
|
|
If you get errors on a system not mentioned above, you will need
|
|
to do some programming or debugging on your own to get the DHCP
|
|
Distribution working.
|
|
|
|
Once you have successfully gotten the DHCP Distribution to build, you
|
|
can install it by typing ``make install''. If you already have an old
|
|
version of the DHCP Distribution installed, you may want to save it
|
|
before typing ``make install''.
|
|
|
|
LINUX
|
|
|
|
There are three big LINUX issues: the all-ones broadcast address,
|
|
Linux 2.1 ip_bootp_agent enabling, and operations with more than one
|
|
network interface. There are also two potential compilation/runtime
|
|
problems for Linux 2.1/2.2: the "SO_ATTACH_FILTER undeclared" problem
|
|
and the "protocol not configured" problem.
|
|
|
|
LINUX: SO_ATTACH_FILTER UNDECLARED
|
|
|
|
In addition, there is a minor issue that we will mention here because
|
|
this release is so close on the heels of the Linux 2.2 release: there
|
|
is a symlink in /usr/include that points at the linux asm headers. It
|
|
appears to be not uncommon that this link won't be updated correctly,
|
|
in which case you'll get the following error when you try to build:
|
|
|
|
lpf.c: In function `if_register_receive':
|
|
lpf.c:152: `SO_ATTACH_FILTER' undeclared (first use this function)
|
|
lpf.c:152: (Each undeclared identifier is reported only once
|
|
lpf.c:152: for each function it appears in.)
|
|
|
|
The line numbers may be different, of course. If you see this
|
|
header, your linux asm header link is probably bad, and you should
|
|
make sure it's pointing to correct linux source directory.
|
|
|
|
LINUX: PROTOCOL NOT CONFIGURED
|
|
|
|
One additional Linux 2.1/2.2 issue: if you get the following message,
|
|
it's because your kernel doesn't have the linux packetfilter or raw
|
|
packet socket configured:
|
|
|
|
Set CONFIG_PACKET=y and CONFIG_FILTER=y in your kernel configuration
|
|
|
|
If this happens, you need to edit your linux kernel .config file, set
|
|
CONFIG_FILTER=y and CONFIG_PACKET=y, and rebuild your kernel. If the
|
|
preceding sentence made no sense to you, ask your Linux vendor/guru
|
|
for help - please don't ask us.
|
|
|
|
If you set CONFIG_PACKET=m or CONFIG_FILTER=m, then you must tell the
|
|
kernel module loader to load the appropriate modules. If this doesn't
|
|
make sense to you, don't use CONFIG_whatever=m - use CONFIG_whatever=y.
|
|
Don't ask for help with this on the DHCP mailing list - it's a Linux
|
|
kernel issue.
|
|
|
|
LINUX: BROADCAST
|
|
|
|
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.
|
|
|
|
It is possible to work around this problem on some versions of Linux
|
|
by creating a host route from your network interface address to
|
|
255.255.255.255. The command you need to use to do this on Linux
|
|
varies from version to version. The easiest version is:
|
|
|
|
route add -host 255.255.255.255 dev eth0
|
|
|
|
On some older Linux systems, you will get an error if you try to do
|
|
this. On those systems, 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
|
|
|
|
Another route that has worked for some users is:
|
|
|
|
route add -net 255.255.255.0 dev eth0
|
|
|
|
If you are not using eth0 as your network interface, you should
|
|
specify the network interface you *are* using in your route command.
|
|
|
|
LINUX: IP BOOTP AGENT
|
|
|
|
Some versions of the Linux 2.1 kernel apparently prevent dhcpd from
|
|
working unless you enable it by doing the following:
|
|
|
|
echo 1 >/proc/sys/net/ipv4/ip_bootp_agent
|
|
|
|
|
|
LINUX: MULTIPLE INTERFACES
|
|
|
|
Most older versions of the Linux kernel do not provide a networking
|
|
API that allows dhcpd to operate correctly if the system has more than
|
|
one broadcast network interface. However, Linux 2.0 kernels with
|
|
version numbers greater than or equal to 2.0.31 add an API feature:
|
|
the SO_BINDTODEVICE socket option. If SO_BINDTODEVICE is present, it
|
|
is possible for dhcpd to operate on Linux with more than one network
|
|
interface. In order to take advantage of this, you must be running a
|
|
2.0.31 or greater kernel, and you must have 2.0.31 or later system
|
|
headers installed *before* you build the DHCP Distribution.
|
|
|
|
We have heard reports that you must still add routes to 255.255.255.255
|
|
in order for the all-ones broadcast to work, even on 2.0.31 kernels.
|
|
In fact, you now need to add a route for each interface. Hopefully
|
|
the Linux kernel gurus will get this straight eventually.
|
|
|
|
SCO
|
|
|
|
SCO has the same problem as Linux (described earlier). The thing is,
|
|
SCO *really* doesn't want to let you add a host route to the all-ones
|
|
broadcast address. One technique that has been successful on some
|
|
versions of SCO is the very bizarre command:
|
|
|
|
ifconfig net0 alias 10.1.1.1 netmask 8.0.0.0
|
|
|
|
Apparently this works because of an interaction between SCO's support
|
|
for network classes and the weird netmask. The 10.* network is just a
|
|
dummy that can generally be assumed to be safe. Don't ask why this
|
|
works. Just try it. If it works for you, great. If not, SCO is
|
|
supposedly adding hooks to support real DHCP service in a future
|
|
release - I have this on good authority from the people at SCO who do
|
|
*their* DHCP server and client.
|
|
|
|
HP-UX
|
|
|
|
HP-UX has the same problem with the all-ones broadcast address that
|
|
SCO and Linux have. One user reported that adding the following to
|
|
/etc/rc.config.d/netconf helped (you may have to modify this to suit
|
|
your local configuration):
|
|
|
|
INTERFACE_NAME[0]=lan0
|
|
IP_ADDRESS[0]=1.1.1.1
|
|
SUBNET_MASK[0]=255.255.255.0
|
|
BROADCAST_ADDRESS[0]="255.255.255.255"
|
|
LANCONFIG_ARGS[0]="ether"
|
|
DHCP_ENABLE[0]=0
|
|
|
|
ULTRIX
|
|
|
|
Now that we have Ultrix packet filter support, the DHCP Distribution
|
|
on Ultrix should be pretty trouble-free. However, one thing you do
|
|
need to be aware of is that it now requires that the pfilt device be
|
|
configured into your kernel and present in /dev. If you type ``man
|
|
packetfilter'', you will get some information on how to configure your
|
|
kernel for the packet filter (if it isn't already) and how to make an
|
|
entry for it in /dev.
|
|
|
|
FreeBSD
|
|
|
|
Versions of FreeBSD prior to 2.2 have a bug in BPF support in that the
|
|
ethernet driver swaps the ethertype field in the ethernet header
|
|
downstream from BPF, which corrupts the output packet. If you are
|
|
running a version of FreeBSD prior to 2.2, and you find that dhcpd
|
|
can't communicate with its clients, you should #define BROKEN_FREEBSD_BPF
|
|
in site.h and recompile.
|
|
|
|
NeXTSTEP
|
|
|
|
The NeXTSTEP support uses the NeXTSTEP Berkeley Packet Filter
|
|
extension, which is not included in the base NextStep system. You
|
|
must install this extension in order to get dhcpd or dhclient to work.
|
|
|
|
SOLARIS
|
|
|
|
One problem which has been observed and is not fixed in this
|
|
patchlevel has to do with using DLPI on Solaris machines. The symptom
|
|
of this problem is that the DHCP server never receives any requests.
|
|
If you are using Solaris 2.6, and you encounter this symptom, and
|
|
you are running the DHCP server on a machine with a single broadcast
|
|
network interface, you may wish to edit the includes/site.h file and
|
|
uncomment the #define USE_SOCKETS line. Then type ``make clean;
|
|
make''.
|
|
|
|
The DHCP client on Solaris will only work with DLPI. If you run it
|
|
and it just keeps saying it's sending DHCPREQUEST packets, but never
|
|
gets a response, you may be having DLPI trouble as described above.
|
|
If so, you are SOL. Also, because Solaris requires you to "plumb" an
|
|
interface before it can be detected by the DHCP client, you must
|
|
either specify the name(s) of the interface(s) you want to configure
|
|
on the command line, or must plumb the interfaces prior to invoking
|
|
the DHCP client. This can be done with ``ifconfig iface plumb'',
|
|
where iface is the name of the interface (e.g., ``ifconfig hme0
|
|
plumb'').
|
|
|
|
It should be noted that Solaris versions from 2.6 onward include a
|
|
DHCP client that you can run with ``/sbin/ifconfig iface dhcp start''
|
|
rather than using the ISC DHCP client. The feature set of the Solaris
|
|
client is different (not necessarily better or worse) than that of the
|
|
ISC client, but in most cases it will be a lot easier for you to just
|
|
use that. Please do not ask for help in using the Solaris DHCP client
|
|
on Internet Software Consortium mailing lists - that's why you're
|
|
paying Sun the big bucks. If you're having a problem with the
|
|
Solaris client interoperating with the ISC dhcp server, that's another
|
|
matter, but please check with Sun first.
|
|
|
|
SUPPORT
|
|
|
|
The Internet Software Consortium DHCP server is not a commercial
|
|
product, and is not supported in that sense. However, it has
|
|
attracted a fairly sizable following on the Internet, which means that
|
|
there are a lot of knowledgable users who may be able to help you if
|
|
you get stuck. These people generally read the dhcp-server@fugue.com
|
|
mailing list.
|
|
|
|
If you are going to use dhcpd, you should probably subscribe to the
|
|
dhcp-server and dhcp-announce mailing lists. If you will be using
|
|
dhclient, you should subscribe to the dhcp-client mailing list.
|
|
PLEASE DO NOT send queries about non-isc clients to the dhcp-client
|
|
mailing list. If you're asking about them on an ISC mailing list,
|
|
it's probably because you're using the ISC DHCP server, so ask there.
|
|
|
|
Please see http://www.fugue.com/dhcp/lists for details on how to
|
|
subscribe. If you don't have WorldWide Web access, you can send mail
|
|
to dhcp-request@fugue.com and tell me which lists you want to
|
|
subscribe to, but please use the web interface if you can, since I
|
|
have to handle the -request mailing list manually, and I will give you
|
|
the third degree if you make me do your subscription manually.
|
|
|
|
PLEASE DO NOT SEND REQUESTS FOR SUPPORT DIRECTLY TO ME! The number of
|
|
people using the DHCP Distribution is sufficiently large that if I
|
|
take an interrupt every time any one of those people runs into
|
|
trouble, I will never get any more coding done.
|
|
|
|
PLEASE DO NOT CALL ME ON THE PHONE FOR SUPPORT! Answering the phone
|
|
takes a lot more of my time and attention than answering email. If you
|
|
do call me on the phone, I will tell you to send email to the mailing
|
|
list, and I won't answer your question, so there's no point in doing
|
|
it.
|
|
|
|
BUGS
|
|
|
|
This release of the DHCP Distribution does not yet contain support for
|
|
DHCPINFORM. Support for DHCPINFORM will be present in the release at
|
|
a later time. DHCPINFORM is somewhat tangential to the main purpose
|
|
of the DHCP protocol, so this probably won't be a major problem for
|
|
most users.
|
|
|
|
Vendor tags and User tags are not currently supported.
|
|
|
|
|