1 Internet Systems Consortium DHCP Distribution 2 Version 4.4.1 3 28 February 2018 4 5 README FILE 6 7You should read this file carefully before trying to install or use 8the ISC DHCP Distribution. 9 10 TABLE OF CONTENTS 11 12 1 WHERE TO FIND DOCUMENTATION 13 2 RELEASE STATUS 14 3 BUILDING THE DHCP DISTRIBUTION 15 3.1 UNPACKING IT 16 3.2 CONFIGURING IT 17 3.2.1 DYNAMIC DNS UPDATES 18 3.2.2 LOCALLY DEFINED OPTIONS 19 3.3 BUILDING IT 20 4 INSTALLING THE DHCP DISTRIBUTION 21 5 USING THE DHCP DISTRIBUTION 22 5.1 FIREWALL RULES 23 5.2 LINUX 24 5.2.1 IF_TR.H NOT FOUND 25 5.2.2 SO_ATTACH_FILTER UNDECLARED 26 5.2.3 PROTOCOL NOT CONFIGURED 27 5.2.4 BROADCAST 28 5.2.6 IP BOOTP AGENT 29 5.2.7 MULTIPLE INTERFACES 30 5.3 SCO 31 5.4 HP-UX 32 5.5 ULTRIX 33 5.6 FreeBSD 34 5.7 NeXTSTEP 35 5.8 SOLARIS 36 5.8.1 Solaris 11 37 5.8.2 Solaris 11 and ATF 38 5.8.3 Other Solaris Items 39 5.9 AIX 40 5.10 MacOS X 41 5.11 ATF 42 6 SUPPORT 43 6.1 HOW TO REPORT BUGS 44 7 HISTORY 45 46 WHERE TO FIND DOCUMENTATION 47 48Documentation for this software includes this README file, the 49RELNOTES file, and the manual pages, which are in the server, common, 50client and relay subdirectories. The README file (this file) includes 51late-breaking operational and system-specific information that you 52should read even if you don't want to read the manual pages, and that 53you should *certainly* read if you run into trouble. Internet 54standards relating to the DHCP protocol are listed in the References 55document that is available in html, txt and xml formats in doc/ 56subdirectory. You will have the best luck reading the manual pages if 57you build this software and then install it, although you can read 58them directly out of the distribution if you need to. 59 60DHCP server documentation is in the dhcpd man page. Information about 61the DHCP server lease database is in the dhcpd.leases man page. 62Server configuration documentation is in the dhcpd.conf man page as 63well as the dhcp-options man page. A sample DHCP server 64configuration is in the file server/dhcpd.conf.example. The source for 65the dhcpd, dhcpd.leases and dhcpd.conf man pages is in the server/ sub- 66directory in the distribution. The source for the dhcp-options.5 67man page is in the common/ subdirectory. 68 69DHCP Client documentation is in the dhclient man page. DHCP client 70configuration documentation is in the dhclient.conf man page and the 71dhcp-options man page. The DHCP client configuration script is 72documented in the dhclient-script man page. The format of the DHCP 73client lease database is documented in the dhclient.leases man page. 74The source for all these man pages is in the client/ subdirectory in 75the distribution. In addition, the dhcp-options man page should be 76referred to for information about DHCP options. 77 78DHCP relay agent documentation is in the dhcrelay man page, the source 79for which is distributed in the relay/ subdirectory. 80 81To read installed manual pages, use the man command. Type "man page" 82where page is the name of the manual page. This will only work if 83you have installed the ISC DHCP distribution using the ``make install'' 84command (described later). 85 86If you want to read manual pages that aren't installed, you can type 87``nroff -man page |more'' where page is the filename of the 88unformatted manual page. The filename of an unformatted manual page 89is the name of the manual page, followed by '.', followed by some 90number - 5 for documentation about files, and 8 for documentation 91about programs. For example, to read the dhcp-options man page, 92you would type ``nroff -man common/dhcp-options.5 |more'', assuming 93your current working directory is the top level directory of the ISC 94DHCP Distribution. 95 96Please note that the pathnames of files to which our manpages refer 97will not be correct for your operating system until after you iterate 98'make install' (so if you're reading a manpage out of the source 99directory, it may not have up-to-date information). 100 101 BUILDING THE DHCP DISTRIBUTION 102 103 UNPACKING IT 104 105To build the DHCP Distribution, unpack the compressed tar file using 106the tar utility and the gzip command - type something like: 107 108 gunzip dhcp-4.4.1.tar.gz 109 tar xvf dhcp-4.4.1.tar 110 111 CONFIGURING IT 112 113Now, cd to the dhcp-4.4.1 subdirectory that you've just created and 114configure the source tree by typing: 115 116 ./configure 117 118If the configure utility can figure out what sort of system you're 119running on, it will create a custom Makefile for you for that 120system; otherwise, it will complain. If it can't figure out what 121system you are using, that system is not supported - you are on 122your own. 123 124Several options may be enabled or disabled via the configure command. 125You can get a list of these by typing: 126 127 ./configure --help 128 129If you want to use dynamic shared libraries automake, autoconf 130(aka GNU autotools) and libtool must be available. The DHCP 131distribution provides 3 configure.ac* files: the -lt version 132has no libtool support and was copied to the configure.ac 133standard file in the distribution. To enable libtool support 134you should perform these steps: 135 136 cp configure.ac+lt configure.ac 137 autoreconf -i 138 139after you can use the regenerated configure as usual 140(with libtool support (--enable-libtool) on by default): 141 142 ./configure 143 144For compatibility (and people who don't read this documentation) 145the --enable-libtool configuration file is supported even by 146the distributed configure (and off by default). The previous 147steps are performed and the regenerated configure called with 148almost the same parameters (this "almost" makes the use of 149this feature not recommended). 150 151Note you can't go back from with libtool support to without libtool 152support by restoring configure.ac and rerun autoreconf. If you 153want or need to restore the without libtool support state the 154required way is to simply restore the whole distribution. 155 156 DYNAMIC DNS UPDATES 157 158A fully-featured implementation of dynamic DNS updates is included in 159this release. It uses libraries from BIND and, to avoid issues with 160different versions, includes the necessary BIND version. The appropriate 161BIND libraries will be compiled and installed in the bind subdirectory 162as part of the make step. In order to build the necessary libraries you 163will need to have "gmake" available on your build system. 164 165 166There is documentation for the DDNS support in the dhcpd.conf manual 167page - see the beginning of this document for information on finding 168manual pages. 169 170 LOCALLY DEFINED OPTIONS 171 172In previous versions of the DHCP server there was a mechanism whereby 173options that were not known by the server could be configured using 174a name made up of the option code number and an identifier: 175"option-nnn" This is no longer supported, because it is not future- 176proof. Instead, if you want to use an option that the server doesn't 177know about, you must explicitly define it using the method described 178in the dhcp-options man page under the DEFINING NEW OPTIONS heading. 179 180 BUILDING IT 181 182Once you've run configure, just type ``make'', and after a while 183you should have a dhcp server. If you get compile errors on one 184of the supported systems mentioned earlier, please let us know. 185If you get warnings, it's not likely to be a problem - the DHCP 186server compiles completely warning-free on as many architectures 187as we can manage, but there are a few for which this is difficult. 188If you get errors on a system not mentioned above, you will need 189to do some programming or debugging on your own to get the DHCP 190Distribution working. 191 192If you cross compile you have to follow the instructions from 193the BIND README, in particular you must set the BUILD_CC 194environment variable. 195 196 INSTALLING THE DHCP DISTRIBUTION 197 198Once you have successfully gotten the DHCP Distribution to build, you 199can install it by typing ``make install''. If you already have an old 200version of the DHCP Distribution installed, you may want to save it 201before typing ``make install''. 202 203 USING THE DHCP DISTRIBUTION 204 205 FIREWALL RULES 206 207If you are running the DHCP server or client on a computer that's also 208acting as a firewall, you must be sure to allow DHCP packets through 209the firewall. In particular, your firewall rules _must_ allow packets 210from IP address 0.0.0.0 to IP address 255.255.255.255 from UDP port 68 211to UDP port 67 through. They must also allow packets from your local 212firewall's IP address and UDP port 67 through to any address your DHCP 213server might serve on UDP port 68. Finally, packets from relay agents 214on port 67 to the DHCP server on port 67, and vice versa, must be 215permitted. 216 217We have noticed that on some systems where we are using a packet 218filter, if you set up a firewall that blocks UDP port 67 and 68 219entirely, packets sent through the packet filter will not be blocked. 220However, unicast packets will be blocked. This can result in strange 221behaviour, particularly on DHCP clients, where the initial packet 222exchange is broadcast, but renewals are unicast - the client will 223appear to be unable to renew until it starts broadcasting its 224renewals, and then suddenly it'll work. The fix is to fix the 225firewall rules as described above. 226 227 PARTIAL SERVERS 228 229If you have a server that is connected to two networks, and you only 230want to provide DHCP service on one of those networks (e.g., you are 231using a cable modem and have set up a NAT router), if you don't write 232any subnet declaration for the network you aren't supporting, the DHCP 233server will ignore input on that network interface if it can. If it 234can't, it will refuse to run - some operating systems do not have the 235capability of supporting DHCP on machines with more than one 236interface, and ironically this is the case even if you don't want to 237provide DHCP service on one of those interfaces. 238 239 LINUX 240 241There are three big LINUX issues: the all-ones broadcast address, 242Linux 2.1 ip_bootp_agent enabling, and operations with more than one 243network interface. There are also two potential compilation/runtime 244problems for Linux 2.1/2.2: the "SO_ATTACH_FILTER undeclared" problem 245and the "protocol not configured" problem. 246 247 LINUX: PROTOCOL NOT CONFIGURED 248 249If you get the following message, it's because your kernel doesn't 250have the Linux packetfilter or raw packet socket configured: 251 252 Make sure CONFIG_PACKET (Packet socket) and CONFIG_FILTER (Socket 253 Filtering) are enabled in your kernel configuration 254 255If this happens, you need to configure your Linux kernel to support 256Socket Filtering and the Packet socket, or to select a kernel provided 257by your Linux distribution that has these enabled (virtually all modern 258ones do by default). 259 260 LINUX: BROADCAST 261 262If you are running a recent version of Linux, this won't be a problem, 263but on older versions of Linux (kernel versions prior to 2.2), there 264is a potential problem with the broadcast address being sent 265incorrectly. 266 267In order for dhcpd to work correctly with picky DHCP clients (e.g., 268Windows 95), it must be able to send packets with an IP destination 269address of 255.255.255.255. Unfortunately, Linux changes an IP 270destination of 255.255.255.255 into the local subnet broadcast address 271(here, that's 192.5.5.223). 272 273This isn't generally a problem on Linux 2.2 and later kernels, since 274we completely bypass the Linux IP stack, but on old versions of Linux 2752.1 and all versions of Linux prior to 2.1, it is a problem - pickier 276DHCP clients connected to the same network as the ISC DHCP server or 277ISC relay agent will not see messages from the DHCP server. It *is* 278possible to run into trouble with this on Linux 2.2 and later if you 279are running a version of the DHCP server that was compiled on a Linux 2802.0 system, though. 281 282It is possible to work around this problem on some versions of Linux 283by creating a host route from your network interface address to 284255.255.255.255. The command you need to use to do this on Linux 285varies from version to version. The easiest version is: 286 287 route add -host 255.255.255.255 dev eth0 288 289On some older Linux systems, you will get an error if you try to do 290this. On those systems, try adding the following entry to your 291/etc/hosts file: 292 293255.255.255.255 all-ones 294 295Then, try: 296 297 route add -host all-ones dev eth0 298 299Another route that has worked for some users is: 300 301 route add -net 255.255.255.0 dev eth0 302 303If you are not using eth0 as your network interface, you should 304specify the network interface you *are* using in your route command. 305 306 LINUX: IP BOOTP AGENT 307 308Some versions of the Linux 2.1 kernel apparently prevent dhcpd from 309working unless you enable it by doing the following: 310 311 echo 1 >/proc/sys/net/ipv4/ip_bootp_agent 312 313 314 LINUX: MULTIPLE INTERFACES 315 316Very old versions of the Linux kernel do not provide a networking API 317that allows dhcpd to operate correctly if the system has more than one 318broadcast network interface. However, Linux 2.0 kernels with version 319numbers greater than or equal to 2.0.31 add an API feature: the 320SO_BINDTODEVICE socket option. If SO_BINDTODEVICE is present, it is 321possible for dhcpd to operate on Linux with more than one network 322interface. In order to take advantage of this, you must be running a 3232.0.31 or greater kernel, and you must have 2.0.31 or later system 324headers installed *before* you build the DHCP Distribution. 325 326We have heard reports that you must still add routes to 255.255.255.255 327in order for the all-ones broadcast to work, even on 2.0.31 kernels. 328In fact, you now need to add a route for each interface. Hopefully 329the Linux kernel gurus will get this straight eventually. 330 331Linux 2.1 and later kernels do not use SO_BINDTODEVICE or require the 332broadcast address hack, but do support multiple interfaces, using the 333Linux Packet Filter. 334 335 LINUX: OpenWrt 336 337DHCP 4.1 has been tested on OpenWrt 7.09 and 8.09. In keeping with 338standard practice, client/scripts now includes a dhclient-script file 339for OpenWrt. However, this is not sufficient by itself to run dhcp on 340OpenWrt; a full OpenWrt package for DHCP is available at 341ftp://ftp.isc.org/isc/dhcp/dhcp-4.1.0-openwrt.tar.gz 342 343 LINUX: 802.1q VLAN INTERFACES 344 345If you're using 802.1q vlan interfaces on Linux, it is necessary to 346vconfig the subinterface(s) to rewrite the 802.1q information out of 347packets received by the dhcpd daemon via LPF: 348 349 vconfig set_flag eth1.523 1 1 350 351Note that this may affect the performance of your system, since the 352Linux kernel must rewrite packets received via this interface. For 353more information, consult the vconfig man pages. 354 355 SCO 356 357ISC DHCP will now work correctly on newer versions of SCO out of the 358box (tested on OpenServer 5.05b, assumed to work on UnixWare 7). 359 360Older versions of SCO have the same problem as Linux (described earlier). 361The thing is, SCO *really* doesn't want to let you add a host route to 362the all-ones broadcast address. 363 364You can try the following: 365 366 ifconfig net0 xxx.xxx.xxx.xxx netmask 0xNNNNNNNN broadcast 255.255.255.255 367 368If this doesn't work, you can also try the following strange hack: 369 370 ifconfig net0 alias 10.1.1.1 netmask 8.0.0.0 371 372Apparently this works because of an interaction between SCO's support 373for network classes and the weird netmask. The 10.* network is just a 374dummy that can generally be assumed to be safe. Don't ask why this 375works. Just try it. If it works for you, great. 376 377 HP-UX 378 379HP-UX has the same problem with the all-ones broadcast address that 380SCO and Linux have. One user reported that adding the following to 381/etc/rc.config.d/netconf helped (you may have to modify this to suit 382your local configuration): 383 384INTERFACE_NAME[0]=lan0 385IP_ADDRESS[0]=1.1.1.1 386SUBNET_MASK[0]=255.255.255.0 387BROADCAST_ADDRESS[0]="255.255.255.255" 388LANCONFIG_ARGS[0]="ether" 389DHCP_ENABLE[0]=0 390 391 ULTRIX 392 393Now that we have Ultrix packet filter support, the DHCP Distribution 394on Ultrix should be pretty trouble-free. However, one thing you do 395need to be aware of is that it now requires that the pfilt device be 396configured into your kernel and present in /dev. If you type ``man 397packetfilter'', you will get some information on how to configure your 398kernel for the packet filter (if it isn't already) and how to make an 399entry for it in /dev. 400 401 FreeBSD 402 403Versions of FreeBSD prior to 2.2 have a bug in BPF support in that the 404ethernet driver swaps the ethertype field in the ethernet header 405downstream from BPF, which corrupts the output packet. If you are 406running a version of FreeBSD prior to 2.2, and you find that dhcpd 407can't communicate with its clients, you should #define BROKEN_FREEBSD_BPF 408in site.h and recompile. 409 410Modern versions of FreeBSD include the ISC DHCP 3.0 client as part of 411the base system, and the full distribution (for the DHCP server and 412relay agent) is available from the Ports Collection in 413/usr/ports/net/isc-dhcp3, or as a package on FreeBSD installation 414CDROMs. 415 416 NeXTSTEP 417 418The NeXTSTEP support uses the NeXTSTEP Berkeley Packet Filter 419extension, which is not included in the base NextStep system. You 420must install this extension in order to get dhcpd or dhclient to work. 421 422 SOLARIS 423 424There are two known issues seen when compiling using the Sun compiler. 425 426The first is that older Sun compilers generate an error on some of 427our uses of the flexible array option. Newer versions only generate 428a warning, which can be safely ignored. If you run into this error 429("type of struct member "buf" can not be derived from structure with 430flexible array member"), upgrade your tools to Oracle Solaris Studio 431(previously Sun Studio) 12 or something newer. 432 433The second is the interaction between the configure script and the 434makefiles for the Bind libraries. Currently we don't pass all 435environment variables between the DHCP configure and the Bind configure. 436 437If you attempt to specify the compiler you wish to use like this: 438 439 CC=/opt/SUNWspro/bin/cc ./configure 440 441"make" may not build the Bind libraries with that compiler. 442 443In order to use the same compiler for Bind and DHCP we suggest the 444following commands: 445 446 CC=/opt/SUNWspro/bin/cc ./configure 447 CC=/opt/SUNWspro/bin/cc make 448 449 Solaris 11 450 451We have integrated a patch from Oracle to use sockets instead of 452DLPI on Solaris 11. This functionality was written for use with 453Solaris Studio 12.2 and requires the system/header package. 454 455By default this code is disabled in order to minimize disruptions 456for current users. In order to enable this code you will need to 457enable both USE_SOCKETS and USE_V4_PKTINFO as part of the 458configuration step. The command line would be something like: 459 460 ./configure --enable-use-sockets --enable-ipv4-pktinfo 461 462 Solaris 11 and ATF 463 464We have reports that ATF 0.15 and 0.16 do not build on Solaris 11. The 465following changes to the ATF source code appear to fix this issue: 466 467diff -ru atf-0.15/atf-c/tp_test.c atf-0.15-patched/atf-c/tp_test.c 468--- atf-0.15/atf-c/tp_test.c 2011-12-06 06:31:11.000000000 +0100 469+++ atf-0.15-patched/atf-c/tp_test.c 2012-06-19 15:54:57.000000000 +0200 470@@ -28,6 +28,7 @@ 471*/ 472 473#include <string.h> 474+#include <stdio.h> 475#include <unistd.h> 476 477#include <atf-c.h> 478 479diff -ru atf-0.15/atf-run/requirements.cpp atf-0.15-patched/atf-run/requirements.cpp 480--- atf-0.15/atf-run/requirements.cpp 2012-01-13 20:44:25.000000000 +0100 481+++ atf-0.15-patched/atf-run/requirements.cpp 2012-06-19 15:41:51.000000000 +0200 482@@ -29,7 +29,7 @@ 483 484extern "C" { 485#include <sys/param.h> 486-#include <sys/sysctl.h> 487+//#include <sys/sysctl.h> 488} 489 490#include <cerrno> 491 492 Other Solaris Items 493 494One problem which has been observed and is not fixed in this 495patchlevel has to do with using DLPI on Solaris machines. The symptom 496of this problem is that the DHCP server never receives any requests. 497This has been observed with Solaris 2.6 and Solaris 7 on Intel x86 498systems, although it may occur with other systems as well. If you 499encounter this symptom, and you are running the DHCP server on a 500machine with a single broadcast network interface, you may wish to 501edit the includes/site.h file and uncomment the #define USE_SOCKETS 502line. Then type ``make clean; make''. As an alternative workaround, 503it has been reported that running 'snoop' will cause the dhcp server 504to start receiving packets. So the practice reported to us is to run 505snoop at dhcpd startup time, with arguments to cause it to receive one 506packet and exit. 507 508 snoop -c 1 udp port 67 > /dev/null & 509 510The DHCP client on Solaris will only work with DLPI. If you run it 511and it just keeps saying it's sending DHCPREQUEST packets, but never 512gets a response, you may be having DLPI trouble as described above. 513If so, we have no solution to offer at this time, aside from the above 514workaround which should also work here. Also, because Solaris requires 515you to "plumb" an interface before it can be detected by the DHCP client, 516you must either specify the name(s) of the interface(s) you want to 517configure on the command line, or must plumb the interfaces prior to 518invoking the DHCP client. This can be done with ``ifconfig iface plumb'', 519where iface is the name of the interface (e.g., ``ifconfig hme0 plumb''). 520 521It should be noted that Solaris versions from 2.6 onward include a 522DHCP client that you can run with ``/sbin/ifconfig iface dhcp start'' 523rather than using the ISC DHCP client, including DHCPv6. Consequently, 524we don't believe there is a need for the client to run on Solaris, and 525have not engineered the needed DHCPv6 modifications for the dhclient-script. 526If you feel this is in error, or have a need, please contact us. 527 528 AIX 529 530The AIX support uses the BSD socket API, which cannot differentiate on 531which network interface a broadcast packet was received; thus the DHCP 532server and relay will work only on a single interface. (They do work 533on multi-interface machines if configured to listen on only one of the 534interfaces.) 535 536We have reports of Windows XP clients having difficulty retrieving 537addresses from a server running on an AIX machine. This issue 538was traced to the client requiring messages be sent to the all ones 539broadcast address (255.255.255.255) while the AIX server was sending 540to 192.168.0.255. 541 542You may be able to solve this by including a relay between the client 543and server with the relay configured to use a broadcast of all-ones. 544 545A second option that worked for AIX 5.1 but doesn't seem to work for 546AIX 5.3 was to: 547 create a host file entry for all-ones (255.255.255.255) 548and then add a route: 549 route add -host all-ones -interface <local-ip-address> 550 551The ISC DHCP distribution does not include a dhclient-script for AIX-- 552AIX comes with a DHCP client. Contribution of a working dhclient-script 553for AIX would be welcome. 554 555 556 MacOS X 557 558The MacOS X system uses a TCP/IP stack derived from FreeBSD with a 559user-friendly interface named the System Configuration Framework. 560As it includes a builtin DHCPv4 client (you are better just using that), 561this text is only about the DHCPv6 client (``dhclient -6 ...''). The DNS 562configuration (domain search list and name servers' addresses) is managed 563by a System Configuration agent, not by /etc/resolv.conf (which is a link 564to /var/run/resolv.conf, which itself only reflects the internal state; 565the System Configuration framework's Dynamic Store). 566 567This means that modifying resolv.conf directly doesn't have the 568intended effect, instead the macos script sample creates its own 569resolv.conf.dhclient6 in /var/run, and inserts the contents of this 570file into the Dynamic Store. 571 572When updating the address configuration the System Configuration 573framework expects the prefix and a default router along with the 574configured address. As this extra information is not available via 575the DHCPv6 protocol the System Configuration framework isn't usable 576for address configuration, instead ifconfig is used directly. 577 578Note the Dynamic Store (from which /var/run/resolv.conf is built) is 579recomputed from scratch when the current location/set is changed. 580Running the dhclient-script reinstalls the resolv.conf.dhclient6 581configuration. 582 583 584 ATF 585 586Please see the file DHCP/doc/devel/atf.dox for a description of building 587and using these tools. 588 589The optional unit tests use ATF (Automated Testing Framework) including 590the atf-run and atf-report tools. ATF deprecated these tools in 591version 0.19 and removed these tools from its sources in version 0.20, 592requiring you to get an older version, use Kyua with an ATF compatibility 593package or use the version included in the Bind sources. 594 595 SUPPORT 596 597The Internet Systems Consortium DHCP server is developed and distributed 598by ISC in the public trust, thanks to the generous donations of its 599sponsors. ISC now also offers commercial quality support contracts for 600ISC DHCP, more information about ISC Support Contracts can be found at 601the following URL: 602 603 https://www.isc.org/services/support/ 604 605Please understand that we may not respond to support inquiries unless 606you have a support contract. ISC will continue its practice of always 607responding to critical items that effect the entire community, and 608responding to all other requests for support upon ISC's mailing lists 609on a best-effort basis. 610 611However, ISC DHCP has attracted a fairly sizable following on the 612Internet, which means that there are a lot of knowledgeable users who 613may be able to help you if you get stuck. These people generally 614read the dhcp-users@isc.org mailing list. Be sure to provide as much 615detail in your query as possible. 616 617If you are going to use ISC DHCP, you should probably subscribe to 618the dhcp-users or dhcp-announce mailing lists. 619 620WHERE TO SEND FEATURE REQUESTS: We like to hear your feedback. We may 621not respond to it all the time, but we do read it. If ISC DHCP doesn't 622work well for you, or you have an idea that would improve it for your 623use, please send your suggestion to dhcp-suggest@isc.org. This is also 624an excellent place to send patches that add new features. 625 626WHERE TO REPORT BUGS: If you want the act of sending in a bug report 627to result in you getting help in the form of a fixed piece of 628software, you are asking for help. Your bug report is helpful to us, 629but fundamentally you are making a support request, so please use the 630addresses described in the previous paragraphs. If you are _sure_ that 631your problem is a bug, and not user error, or if your bug report 632includes a patch, you can send it to our ticketing system at 633dhcp-bugs@isc.org. If you have not received a notice that the ticket 634has been resolved, then we're still working on it. 635 636PLEASE DO NOT REPORT BUGS IN OLD SOFTWARE RELEASES! Fetch the latest 637release and see if the bug is still in that version of the software, 638and if it is still present, _then_ report it. ISC release versions 639always have three numbers, for example: 1.2.3. The 'major release' is 6401 here, the 'minor release' is 2, and the 'maintenance release' is 3. 641ISC will accept bug reports against the most recent two major.minor 642releases: for example, 1.0.0 and 0.9.0, but not 0.8.* or prior. 643 644PLEASE take a moment to determine where the ISC DHCP distribution 645that you're using came from. ISC DHCP is sometimes heavily modified 646by integrators in various operating systems - it's not that we 647feel that our software is perfect and incapable of having bugs, but 648rather that it is very frustrating to find out after many days trying 649to help someone that the sources you're looking at aren't what they're 650running. When in doubt, please retrieve the source distribution from 651ISC's web page and install it. 652 653 HOW TO REPORT BUGS OR REQUEST HELP 654 655When you report bugs or ask for help, please provide us complete 656information. A list of information we need follows. Please read it 657carefully, and put all the information you can into your initial bug 658report. This will save us a great deal of time and more informative 659bug reports are more likely to get handled more quickly overall. 660 661 1. The specific operating system name and version of the 662 machine on which the DHCP server or client is running. 663 2. The specific operating system name and version of the 664 machine on which the client is running, if you are having 665 trouble getting a client working with the server. 666 3. If you're running Linux, the version number we care about is 667 the kernel version and maybe the library version, not the 668 distribution version - e.g., while we don't mind knowing 669 that you're running Redhat version mumble.foo, we must know 670 what kernel version you're running, and it helps if you can 671 tell us what version of the C library you're running, 672 although if you don't know that off the top of your head it 673 may be hard for you to figure it out, so don't go crazy 674 trying. 675 4. The specific version of the DHCP distribution you're 676 running, as reported by dhcpd -t. 677 5. Please explain the problem carefully, thinking through what 678 you're saying to ensure that you don't assume we know 679 something about your situation that we don't know. 680 6. Include your dhcpd.conf and dhcpd.leases file as MIME attachments 681 if they're not over 100 kilobytes in size each. If they are 682 this large, please make them available to us, e.g., via a hidden 683 http:// URL or FTP site. If you're not comfortable releasing 684 this information due to sensitive contents, you may encrypt 685 the file to our release signing key, available on our website. 686 7. Include a log of your server or client running until it 687 encounters the problem - for example, if you are having 688 trouble getting some client to get an address, restart the 689 server with the -d flag and then restart the client, and 690 send us what the server prints. Likewise, with the client, 691 include the output of the client as it fails to get an 692 address or otherwise does the wrong thing. Do not leave 693 out parts of the output that you think aren't interesting. 694 8. If the client or server is dumping core, please run the 695 debugger and get a stack trace, and include that in your 696 bug report. For example, if your debugger is gdb, do the 697 following: 698 699 gdb dhcpd dhcpd.core 700 (gdb) where 701 [...] 702 (gdb) quit 703 704 This assumes that it's the dhcp server you're debugging, and 705 that the core file is in dhcpd.core. 706 707Please see https://www.isc.org/software/dhcp/ for details on how to subscribe 708to the ISC DHCP mailing lists. 709 710 HISTORY 711 712ISC DHCP was originally written by Ted Lemon under a contract with 713Vixie Labs with the goal of being a complete reference implementation 714of the DHCP protocol. Funding for this project was provided by 715Internet Systems Consortium. The first release of the ISC DHCP 716distribution in December 1997 included just the DHCP server. 717Release 2 in June 1999 added a DHCP client and a BOOTP/DHCP relay 718agent. DHCP 3 was released in October 2001 and included DHCP failover 719support, OMAPI, Dynamic DNS, conditional behaviour, client classing, 720and more. Version 3 of the DHCP server was funded by Nominum, Inc. 721The 4.0 release in December 2007 introduced DHCPv6 protocol support 722for the server and client. 723 724This product includes cryptographic software written 725by Eric Young (eay@cryptsoft.com). 726