1 Internet Systems Consortium DHCP Distribution
7 You should read this file carefully before trying to install or use
8 the ISC DHCP Distribution.
12 1 WHERE TO FIND DOCUMENTATION
14 3 BUILDING THE DHCP DISTRIBUTION
17 3.2.1 DYNAMIC DNS UPDATES
18 3.2.2 LOCALLY DEFINED OPTIONS
20 4 INSTALLING THE DHCP DISTRIBUTION
21 5 USING THE DHCP DISTRIBUTION
24 5.2.1 IF_TR.H NOT FOUND
25 5.2.2 SO_ATTACH_FILTER UNDECLARED
26 5.2.3 PROTOCOL NOT CONFIGURED
29 5.2.7 MULTIPLE INTERFACES
37 5.8.2 Other Solaris Items
41 6.1 HOW TO REPORT BUGS
43 WHERE TO FIND DOCUMENTATION
45 Documentation for this software includes this README file, the
46 RELNOTES file, and the manual pages, which are in the server, common,
47 client and relay subdirectories. The README file (this file) includes
48 late-breaking operational and system-specific information that you
49 should read even if you don't want to read the manual pages, and that
50 you should *certainly* read if you run into trouble. Internet
51 standards relating to the DHCP protocol are listed in the References
52 document that is available in html, txt and xml formats in doc/
53 subdirectory. You will have the best luck reading the manual pages if
54 you build this software and then install it, although you can read
55 them directly out of the distribution if you need to.
57 DHCP server documentation is in the dhcpd man page. Information about
58 the DHCP server lease database is in the dhcpd.leases man page.
59 Server configuration documentation is in the dhcpd.conf man page as
60 well as the dhcp-options man page. A sample DHCP server
61 configuration is in the file server/dhcpd.conf. The source for the
62 dhcpd, dhcpd.leases and dhcpd.conf man pages is in the server/ sub-
63 directory in the distribution. The source for the dhcp-options.5
64 man page is in the common/ subdirectory.
66 DHCP Client documentation is in the dhclient man page. DHCP client
67 configuration documentation is in the dhclient.conf man page and the
68 dhcp-options man page. The DHCP client configuration script is
69 documented in the dhclient-script man page. The format of the DHCP
70 client lease database is documented in the dhclient.leases man page.
71 The source for all these man pages is in the client/ subdirectory in
72 the distribution. In addition, the dhcp-options man page should be
73 referred to for information about DHCP options.
75 DHCP relay agent documentation is in the dhcrelay man page, the source
76 for which is distributed in the relay/ subdirectory.
78 To read installed manual pages, use the man command. Type "man page"
79 where page is the name of the manual page. This will only work if
80 you have installed the ISC DHCP distribution using the ``make install''
81 command (described later).
83 If you want to read manual pages that aren't installed, you can type
84 ``nroff -man page |more'' where page is the filename of the
85 unformatted manual page. The filename of an unformatted manual page
86 is the name of the manual page, followed by '.', followed by some
87 number - 5 for documentation about files, and 8 for documentation
88 about programs. For example, to read the dhcp-options man page,
89 you would type ``nroff -man common/dhcp-options.5 |more'', assuming
90 your current working directory is the top level directory of the ISC
93 Please note that the pathnames of files to which our manpages refer
94 will not be correct for your operating system until after you iterate
95 'make install' (so if you're reading a manpage out of the source
96 directory, it may not have up-to-date information).
100 This is ISC DHCP 4.2.3-P2, a security release containing one security
101 patch to fix a potential DOS issue.
103 In this release, the DHCPv6 server should be fully functional on Linux,
104 Solaris, or any BSD. The DHCPv6 client should be similarly functional
107 The DHCPv4 server, relay, and client, should be fully functional
108 on Linux, Solaris, any BSD, HPUX, SCO, NextSTEP, and Irix.
110 If you are running the DHCP distribution on a machine which is a
111 firewall, or if there is a firewall between your DHCP server(s) and
112 DHCP clients, please read the section on firewalls which appears later
115 If you wish to run the DHCP Distribution on Linux, please see the
116 Linux-specific notes later in this document. If you wish to run on an
117 SCO release, please see the SCO-specific notes later in this document.
118 You particularly need to read these notes if you intend to support
119 Windows 95 clients. If you are running HP-UX or Ultrix, please read the
120 notes for those operating systems below. If you are running NeXTSTEP,
121 please see the notes on NeXTSTEP below.
123 If you start dhcpd and get a message, "no free bpf", that means you
124 need to configure the Berkeley Packet Filter into your operating
125 system kernel. On NetBSD, FreeBSD and BSD/os, type ``man bpf'' for
126 information. On Digital Unix, type ``man pfilt''.
129 BUILDING THE DHCP DISTRIBUTION
133 To build the DHCP Distribution, unpack the compressed tar file using
134 the tar utility and the gzip command - type something like:
136 gunzip dhcp-4.2.3-P2.tar.gz
137 tar xvf dhcp-4.2.3-P2.tar
141 Now, cd to the dhcp-4.2.3-P2 subdirectory that you've just created and
142 configure the source tree by typing:
146 If the configure utility can figure out what sort of system you're
147 running on, it will create a custom Makefile for you for that
148 system; otherwise, it will complain. If it can't figure out what
149 system you are using, that system is not supported - you are on
154 A fully-featured implementation of dynamic DNS updates is included in
155 this release. It uses libraries from BIND and, to avoid issues with
156 different versions, includes the necessary BIND version. The appropriate
157 BIND libraries will be compiled and installed in the bind subdirectory
158 as part of the make step. In order to build the necessary libraries you
159 will need to have "gmake" available on your build system.
162 There is documentation for the DDNS support in the dhcpd.conf manual
163 page - see the beginning of this document for information on finding
166 LOCALLY DEFINED OPTIONS
168 In previous versions of the DHCP server there was a mechanism whereby
169 options that were not known by the server could be configured using
170 a name made up of the option code number and an identifier:
171 "option-nnn" This is no longer supported, because it is not future-
172 proof. Instead, if you want to use an option that the server doesn't
173 know about, you must explicitly define it using the method described
174 in the dhcp-options man page under the DEFINING NEW OPTIONS heading.
178 Once you've run configure, just type ``make'', and after a while
179 you should have a dhcp server. If you get compile errors on one
180 of the supported systems mentioned earlier, please let us know.
181 If you get warnings, it's not likely to be a problem - the DHCP
182 server compiles completely warning-free on as many architectures
183 as we can manage, but there are a few for which this is difficult.
184 If you get errors on a system not mentioned above, you will need
185 to do some programming or debugging on your own to get the DHCP
186 Distribution working.
188 INSTALLING THE DHCP DISTRIBUTION
190 Once you have successfully gotten the DHCP Distribution to build, you
191 can install it by typing ``make install''. If you already have an old
192 version of the DHCP Distribution installed, you may want to save it
193 before typing ``make install''.
195 USING THE DHCP DISTRIBUTION
199 If you are running the DHCP server or client on a computer that's also
200 acting as a firewall, you must be sure to allow DHCP packets through
201 the firewall. In particular, your firewall rules _must_ allow packets
202 from IP address 0.0.0.0 to IP address 255.255.255.255 from UDP port 68
203 to UDP port 67 through. They must also allow packets from your local
204 firewall's IP address and UDP port 67 through to any address your DHCP
205 server might serve on UDP port 68. Finally, packets from relay agents
206 on port 67 to the DHCP server on port 67, and vice versa, must be
209 We have noticed that on some systems where we are using a packet
210 filter, if you set up a firewall that blocks UDP port 67 and 68
211 entirely, packets sent through the packet filter will not be blocked.
212 However, unicast packets will be blocked. This can result in strange
213 behaviour, particularly on DHCP clients, where the initial packet
214 exchange is broadcast, but renewals are unicast - the client will
215 appear to be unable to renew until it starts broadcasting its
216 renewals, and then suddenly it'll work. The fix is to fix the
217 firewall rules as described above.
221 If you have a server that is connected to two networks, and you only
222 want to provide DHCP service on one of those networks (e.g., you are
223 using a cable modem and have set up a NAT router), if you don't write
224 any subnet declaration for the network you aren't supporting, the DHCP
225 server will ignore input on that network interface if it can. If it
226 can't, it will refuse to run - some operating systems do not have the
227 capability of supporting DHCP on machines with more than one
228 interface, and ironically this is the case even if you don't want to
229 provide DHCP service on one of those interfaces.
233 There are three big LINUX issues: the all-ones broadcast address,
234 Linux 2.1 ip_bootp_agent enabling, and operations with more than one
235 network interface. There are also two potential compilation/runtime
236 problems for Linux 2.1/2.2: the "SO_ATTACH_FILTER undeclared" problem
237 and the "protocol not configured" problem.
239 LINUX: PROTOCOL NOT CONFIGURED
241 If you get the following message, it's because your kernel doesn't
242 have the linux packetfilter or raw packet socket configured:
244 Make sure CONFIG_PACKET (Packet socket) and CONFIG_FILTER (Socket
245 Filtering) are enabled in your kernel configuration
247 If this happens, you need to configure your Linux kernel to support
248 Socket Filtering and the Packet socket, or to select a kernel provided
249 by your Linux distribution that has these enabled (virtually all modern
254 If you are running a recent version of Linux, this won't be a problem,
255 but on older versions of Linux (kernel versions prior to 2.2), there
256 is a potential problem with the broadcast address being sent
259 In order for dhcpd to work correctly with picky DHCP clients (e.g.,
260 Windows 95), it must be able to send packets with an IP destination
261 address of 255.255.255.255. Unfortunately, Linux changes an IP
262 destination of 255.255.255.255 into the local subnet broadcast address
263 (here, that's 192.5.5.223).
265 This isn't generally a problem on Linux 2.2 and later kernels, since
266 we completely bypass the Linux IP stack, but on old versions of Linux
267 2.1 and all versions of Linux prior to 2.1, it is a problem - pickier
268 DHCP clients connected to the same network as the ISC DHCP server or
269 ISC relay agent will not see messages from the DHCP server. It *is*
270 possible to run into trouble with this on Linux 2.2 and later if you
271 are running a verson of the DHCP server that was compiled on a Linux
274 It is possible to work around this problem on some versions of Linux
275 by creating a host route from your network interface address to
276 255.255.255.255. The command you need to use to do this on Linux
277 varies from version to version. The easiest version is:
279 route add -host 255.255.255.255 dev eth0
281 On some older Linux systems, you will get an error if you try to do
282 this. On those systems, try adding the following entry to your
285 255.255.255.255 all-ones
289 route add -host all-ones dev eth0
291 Another route that has worked for some users is:
293 route add -net 255.255.255.0 dev eth0
295 If you are not using eth0 as your network interface, you should
296 specify the network interface you *are* using in your route command.
298 LINUX: IP BOOTP AGENT
300 Some versions of the Linux 2.1 kernel apparently prevent dhcpd from
301 working unless you enable it by doing the following:
303 echo 1 >/proc/sys/net/ipv4/ip_bootp_agent
306 LINUX: MULTIPLE INTERFACES
308 Very old versions of the Linux kernel do not provide a networking API
309 that allows dhcpd to operate correctly if the system has more than one
310 broadcast network interface. However, Linux 2.0 kernels with version
311 numbers greater than or equal to 2.0.31 add an API feature: the
312 SO_BINDTODEVICE socket option. If SO_BINDTODEVICE is present, it is
313 possible for dhcpd to operate on Linux with more than one network
314 interface. In order to take advantage of this, you must be running a
315 2.0.31 or greater kernel, and you must have 2.0.31 or later system
316 headers installed *before* you build the DHCP Distribution.
318 We have heard reports that you must still add routes to 255.255.255.255
319 in order for the all-ones broadcast to work, even on 2.0.31 kernels.
320 In fact, you now need to add a route for each interface. Hopefully
321 the Linux kernel gurus will get this straight eventually.
323 Linux 2.1 and later kernels do not use SO_BINDTODEVICE or require the
324 broadcast address hack, but do support multiple interfaces, using the
329 DHCP 4.1 has been tested on OpenWrt 7.09 and 8.09. In keeping with
330 standard practice, client/scripts now includes a dhclient-script file
331 for OpenWrt. However, this is not sufficient by itself to run dhcp on
332 OpenWrt; a full OpenWrt package for DHCP is available at
333 ftp://ftp.isc.org/isc/dhcp/dhcp-4.1.0-openwrt.tar.gz
335 LINUX: 802.1q VLAN INTERFACES
337 If you're using 802.1q vlan interfaces on Linux, it is necessary to
338 vconfig the subinterface(s) to rewrite the 802.1q information out of
339 packets received by the dhcpd daemon via LPF:
341 vconfig set_flag eth1.523 1 1
343 Note that this may affect the performance of your system, since the
344 Linux kernel must rewrite packets received via this interface. For
345 more information, consult the vconfig man pages.
349 ISC DHCP will now work correctly on newer versions of SCO out of the
350 box (tested on OpenServer 5.05b, assumed to work on UnixWare 7).
352 Older versions of SCO have the same problem as Linux (described earlier).
353 The thing is, SCO *really* doesn't want to let you add a host route to
354 the all-ones broadcast address.
356 You can try the following:
358 ifconfig net0 xxx.xxx.xxx.xxx netmask 0xNNNNNNNN broadcast 255.255.255.255
360 If this doesn't work, you can also try the following strange hack:
362 ifconfig net0 alias 10.1.1.1 netmask 8.0.0.0
364 Apparently this works because of an interaction between SCO's support
365 for network classes and the weird netmask. The 10.* network is just a
366 dummy that can generally be assumed to be safe. Don't ask why this
367 works. Just try it. If it works for you, great.
371 HP-UX has the same problem with the all-ones broadcast address that
372 SCO and Linux have. One user reported that adding the following to
373 /etc/rc.config.d/netconf helped (you may have to modify this to suit
374 your local configuration):
376 INTERFACE_NAME[0]=lan0
377 IP_ADDRESS[0]=1.1.1.1
378 SUBNET_MASK[0]=255.255.255.0
379 BROADCAST_ADDRESS[0]="255.255.255.255"
380 LANCONFIG_ARGS[0]="ether"
385 Now that we have Ultrix packet filter support, the DHCP Distribution
386 on Ultrix should be pretty trouble-free. However, one thing you do
387 need to be aware of is that it now requires that the pfilt device be
388 configured into your kernel and present in /dev. If you type ``man
389 packetfilter'', you will get some information on how to configure your
390 kernel for the packet filter (if it isn't already) and how to make an
391 entry for it in /dev.
395 Versions of FreeBSD prior to 2.2 have a bug in BPF support in that the
396 ethernet driver swaps the ethertype field in the ethernet header
397 downstream from BPF, which corrupts the output packet. If you are
398 running a version of FreeBSD prior to 2.2, and you find that dhcpd
399 can't communicate with its clients, you should #define BROKEN_FREEBSD_BPF
400 in site.h and recompile.
402 Modern versions of FreeBSD include the ISC DHCP 3.0 client as part of
403 the base system, and the full distribution (for the DHCP server and
404 relay agent) is available from the Ports Collection in
405 /usr/ports/net/isc-dhcp3, or as a package on FreeBSD installation
410 The NeXTSTEP support uses the NeXTSTEP Berkeley Packet Filter
411 extension, which is not included in the base NextStep system. You
412 must install this extension in order to get dhcpd or dhclient to work.
416 There are two known issues seen when compiling using the Sun compiler.
418 The first is that older Sun compilers generate an error on some of
419 our uses of the flexible array option. Newer versions only generate
420 a warning, which can be safely ignored. If you run into this error
421 ("type of struct member "buf" can not be derived from structure with
422 flexible array member"), upgrade your tools to Oracle Solaris Studio
423 (previously Sun Studio) 12 or something newer.
425 The second is the interaction between the configure script and the
426 makefiles for the Bind libraries. Currently we don't pass all
427 environment variables between the DHCP configure and the Bind configure.
429 If you attempt to specify the compiler you wish to use like this:
431 CC=/opt/SUNWspro/bin/cc ./configure
433 "make" may not build the Bind libraries with that compiler.
435 In order to use the same compiler for Bind and DHCP we suggest the
438 CC=/opt/SUNWspro/bin/cc ./configure
439 CC=/opt/SUNWspro/bin/cc make
443 We have integrated a patch from Oracle to use sockets instead of
444 DLPI on Solaris 11. This functionality was written for use with
445 Solaris Studio 12.2 and requires the system/header package.
447 By default this code is disabled in order to minimize disruptions
448 for current users. In order to enable this code you will need to
449 enable both USE_SOCKETS and USE_V4_PKTINFO as part of the
450 configuration step. The command line would be something like:
452 ./configure --enable-use-sockets --enable-ipv4-pktinfo
456 One problem which has been observed and is not fixed in this
457 patchlevel has to do with using DLPI on Solaris machines. The symptom
458 of this problem is that the DHCP server never receives any requests.
459 This has been observed with Solaris 2.6 and Solaris 7 on Intel x86
460 systems, although it may occur with other systems as well. If you
461 encounter this symptom, and you are running the DHCP server on a
462 machine with a single broadcast network interface, you may wish to
463 edit the includes/site.h file and uncomment the #define USE_SOCKETS
464 line. Then type ``make clean; make''. As an alternative workaround,
465 it has been reported that running 'snoop' will cause the dhcp server
466 to start receiving packets. So the practice reported to us is to run
467 snoop at dhcpd startup time, with arguments to cause it to receive one
470 snoop -c 1 udp port 67 > /dev/null &
472 The DHCP client on Solaris will only work with DLPI. If you run it
473 and it just keeps saying it's sending DHCPREQUEST packets, but never
474 gets a response, you may be having DLPI trouble as described above.
475 If so, we have no solution to offer at this time, aside from the above
476 workaround which should also work here. Also, because Solaris requires
477 you to "plumb" an interface before it can be detected by the DHCP client,
478 you must either specify the name(s) of the interface(s) you want to
479 configure on the command line, or must plumb the interfaces prior to
480 invoking the DHCP client. This can be done with ``ifconfig iface plumb'',
481 where iface is the name of the interface (e.g., ``ifconfig hme0 plumb'').
483 It should be noted that Solaris versions from 2.6 onward include a
484 DHCP client that you can run with ``/sbin/ifconfig iface dhcp start''
485 rather than using the ISC DHCP client, including DHCPv6. Consequently,
486 we don't believe there is a need for the client to run on Solaris, and
487 have not engineered the needed DHCPv6 modifications for the dhclient-script.
488 If you feel this is in error, or have a need, please contact us.
492 The AIX support uses the BSD socket API, which cannot differentiate on
493 which network interface a broadcast packet was received; thus the DHCP
494 server and relay will work only on a single interface. (They do work
495 on multi-interface machines if configured to listen on only one of the
498 We have reports of Windows XP clients having difficutly retrieving
499 addresses from a server running on an AIX machine. This issue
500 was traced to the client requiring messages be sent to the all ones
501 broadcast address (255.255.255.255) while the AIX server was sending
504 You may be able to solve this by including a relay between the client
505 and server with the relay configured to use a broadcast of all-ones.
507 A second option that worked for AIX 5.1 but doesn't seem to work for
509 create a host file entry for all-ones (255.255.255.255)
510 and then add a route:
511 route add -host all-ones -interface <local-ip-address>
513 The ISC DHCP distribution does not include a dhclient-script for AIX--
514 AIX comes with a DHCP client. Contribution of a working dhclient-script
515 for AIX would be welcome.
520 The MacOS X system uses a TCP/IP stack derived from FreeBSD with a
521 user-friendly interface named the System Configuration Framework.
522 As it includes a builtin DHCPv4 client (you are better just using that),
523 this text is only about the DHCPv6 client (``dhclient -6 ...''). The DNS
524 configuration (domain search list and name servers' addresses) is managed
525 by a System Configuration agent, not by /etc/resolv.conf (which is a link
526 to /var/run/resolv.conf, which itself only reflects the internal state;
527 the System Configuration framework's Dynamic Store).
529 This means that modifying resolv.conf directly doesn't have the
530 intended effect, instead the macos script sample creates its own
531 resolv.conf.dhclient6 in /var/run, and inserts the contents of this
532 file into the Dynamic Store.
534 When updating the address configuration the System Configuration
535 framework expects the prefix and a default router along with the
536 configured address. As this extra information is not available via
537 the DHCPv6 protocol the System Configuration framework isn't usable
538 for address configuration, instead ifconfig is used directly.
540 Note the Dynamic Store (from which /var/run/resolv.conf is built) is
541 recomputed from scratch when the current location/set is changed.
542 Running the dhclient-script reinstalls the resolv.conf.dhclient6
547 The Internet Systems Consortium DHCP server is developed and distributed
548 by ISC in the public trust, thanks to the generous donations of its
549 sponsors. ISC now also offers commercial quality support contracts for
550 ISC DHCP, more information about ISC Support Contracts can be found at
553 https://www.isc.org/services/support/
555 Please understand that we may not respond to support inquiries unless
556 you have a support contract. ISC will continue its practice of always
557 responding to critical items that effect the entire community, and
558 responding to all other requests for support upon ISC's mailing lists
559 on a best-effort basis.
561 However, ISC DHCP has attracted a fairly sizable following on the
562 Internet, which means that there are a lot of knowledgeable users who
563 may be able to help you if you get stuck. These people generally
564 read the dhcp-users@isc.org mailing list. Be sure to provide as much
565 detail in your query as possible.
567 If you are going to use ISC DHCP, you should probably subscribe to
568 the dhcp-users or dhcp-announce mailing lists.
570 WHERE TO SEND FEATURE REQUESTS: We like to hear your feedback. We may
571 not respond to it all the time, but we do read it. If ISC DHCP doesn't
572 work well for you, or you have an idea that would improve it for your
573 use, please send your suggestion to dhcp-suggest@isc.org. This is also
574 an excellent place to send patches that add new features.
576 WHERE TO REPORT BUGS: If you want the act of sending in a bug report
577 to result in you getting help in the form of a fixed piece of
578 software, you are asking for help. Your bug report is helpful to us,
579 but fundamentally you are making a support request, so please use the
580 addresses described in the previous paragraphs. If you are _sure_ that
581 your problem is a bug, and not user error, or if your bug report
582 includes a patch, you can send it to our ticketing system at
583 dhcp-bugs@isc.org. If you have not received a notice that the ticket
584 has been resolved, then we're still working on it.
586 PLEASE DO NOT REPORT BUGS IN OLD SOFTWARE RELEASES! Fetch the latest
587 release and see if the bug is still in that version of the software,
588 and if it is still present, _then_ report it. ISC release versions
589 always have three numbers, for example: 1.2.3. The 'major release' is
590 1 here, the 'minor release' is 2, and the 'maintenance release' is 3.
591 ISC will accept bug reports against the most recent two major.minor
592 releases: for example, 1.0.0 and 0.9.0, but not 0.8.* or prior.
594 PLEASE take a moment to determine where the ISC DHCP distribution
595 that you're using came from. ISC DHCP is sometimes heavily modified
596 by integrators in various operating systems - it's not that we
597 feel that our software is perfect and incapable of having bugs, but
598 rather that it is very frustrating to find out after many days trying
599 to help someone that the sources you're looking at aren't what they're
600 running. When in doubt, please retrieve the source distribution from
601 ISC's web page and install it.
603 HOW TO REPORT BUGS OR REQUEST HELP
605 When you report bugs or ask for help, please provide us complete
606 information. A list of information we need follows. Please read it
607 carefully, and put all the information you can into your initial bug
608 report. This will save us a great deal of time and more informative
609 bug reports are more likely to get handled more quickly overall.
611 1. The specific operating system name and version of the
612 machine on which the DHCP server or client is running.
613 2. The specific operating system name and version of the
614 machine on which the client is running, if you are having
615 trouble getting a client working with the server.
616 3. If you're running Linux, the version number we care about is
617 the kernel version and maybe the library version, not the
618 distribution version - e.g., while we don't mind knowing
619 that you're running Redhat version mumble.foo, we must know
620 what kernel version you're running, and it helps if you can
621 tell us what version of the C library you're running,
622 although if you don't know that off the top of your head it
623 may be hard for you to figure it out, so don't go crazy
625 4. The specific version of the DHCP distribution you're
626 running, as reported by dhcpd -t.
627 5. Please explain the problem carefully, thinking through what
628 you're saying to ensure that you don't assume we know
629 something about your situation that we don't know.
630 6. Include your dhcpd.conf and dhcpd.leases file as MIME attachments
631 if they're not over 100 kilobytes in size each. If they are
632 this large, please make them available to us eg via a hidden
633 http:// URL or FTP site. If you're not comfortable releasing
634 this information due to sensitive contents, you may encrypt
635 the file to our release signing key, available on our website.
636 7. Include a log of your server or client running until it
637 encounters the problem - for example, if you are having
638 trouble getting some client to get an address, restart the
639 server with the -d flag and then restart the client, and
640 send us what the server prints. Likewise, with the client,
641 include the output of the client as it fails to get an
642 address or otherwise does the wrong thing. Do not leave
643 out parts of the output that you think aren't interesting.
644 8. If the client or server is dumping core, please run the
645 debugger and get a stack trace, and include that in your
646 bug report. For example, if your debugger is gdb, do the
654 This assumes that it's the dhcp server you're debugging, and
655 that the core file is in dhcpd.core.
657 Please see https://www.isc.org/software/dhcp/ for details on how to subscribe
658 to the ISC DHCP mailing lists.