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	    Internet Software Consortium DHCP Distribution
		    Version 3, Release Candidate 4
			    April 30, 2001

			    Release Notes

This is a development snapshot of Version 3 of the Internet Software
Consortium DHCP Distribution.

			     NEW FEATURES

Version 3 of the ISC DHCP Distribution includes the following features
that are new since version 2.0:

     - DHCP Failover Protocol support
     - OMAPI, an API for accessing and modifying the DHCP server and
       client state.
     - Conditional behaviour
     - Storing arbitrary information on leases
     - Address pools with access control
     - Client classing
     - Address allocation restriction by class
     - Relay agent information option support 
     - Dynamic DNS updates
     - Many bug fixes, performance enhancements, and minor new DHCP
       protocol features. 

This release has been beta tested quite thorougly, and we think it is
substantially more robust at this time than 2.0pl5.  The release
candidate is expected to be free of serious bugs, but it's called a
release candidate because we want people to try it and find any last
real problems before we call it done.  We do not expect to add
anything other than documentation and any remaining bug fixes to the
3.0 release.  

The 3.0 Release Candidate 1 lease file is not backwards compatible
with the 3.0 Beta 1 lease file, so if you have to go back, you will
have to convert your lease files back to the 3.0 Beta 1 format - if
you try to run a 3.0 Beta 1 server on a 3.0 lease file, it will
cheerfully delete all your leases.

If you are running 3.0 beta 1 and are doing dynamic DNS updates, the
lease file is no longer forward-compatible to 3.0 final.   A script
has been provided to convert 3.0b1 lease files.   This is in
contrib/3.0b1-lease-convert.

For information on how to install, configure and run this software,
as well as how to find documentation and report bugs, please consult
the README file.

The Dynamic DNS Update support is a descendent of an implementation
done by Lans Carstensen and Brian Dols at Rose-Hulman Institute of
Technology, Jim Watt at Applied Biosystems, Irina Goble at Integrated
Measurement Systems, Igor Sharfmesser at Kazakh Telecom, and Brian
Murrell at BC Tel Advanced Communications.  I'd like to express my
thanks to all of these good people here, both for working on the code
and for prodding me into improving it.

	  Changes since 3.0 Release Candidate 8 Patchlevel 1

- Fix a parsing bug that broke dns updates (both interim and ad-hoc).
  This was introduced in rc8pl1 as an unintended result of the memory
  leakage fixes that were in pl1.

- Fix a long-standing bug where the server would record that an update
  had been done for a client with no name, even though no update had
  been done, and then when the client's lease expired the deletion of
  that nonexistant record would time out because the name was the null
  string. 

- Clean up the omshell, dhcpctl and omapi man pages a bit.


		Changes since 3.0 Release Candidate 8

- Fix a bug that could cause the DHCP server to spin if
  one-lease-per-client was enabled.

- Fix a bug that was causing core dumps on BSD/os in the presence of
  malformed packets.

- In partner-down state, don't restrict lease lengths to MCLT.

- On the failover secondary, record the MCLT received from the primary
  so that if we come up without a connection to the primary we don't
  wind up giving out zero-length leases.

- Fix some compilation problems on BSD/os.

- Fix a bunch of memory leaks.

- Fix a couple of bugs in the option printer.

- Fix an obscure error reporting bug in the dns update code, and also
  make the message clearer when a key algorithm isn't supported.

- Fix a bug in the tracing code that prevented trace runs that used
  tcp connections from being played back.

- Add some additional debugging capability for catching memory leaks
  on exit.

- Make the client release the lease correctly on shutdown.

- Add some configurability to the build system.

- Install omshell manual page in man1, not man8.

- Craig Gwydir sent in a patch that fixes a long-standing bug in the
  DHCP client that could cause core dumps, but that for some reason
  hadn't been noticed until now.

		Changes since 3.0 Release Candidate 7

- Fix a bug in failover where we weren't sending updates after a
  transition from communications-interrupted to normal.

- Handle expired/released/reset -> free transition according to the
  protocol specification (this works - the other way not only wasn't
  conformant, but also didn't work).

- Add a control object in both client and server that allows either
  daemon to be shut down cleanly.

- When writing a lease, if we run out of disk space, shut down the
  output file and insist on writing a new one before proceeding.

- In the server, if the OMAPI listener port is occupied, keep trying
  to get it, rather than simply giving up and exiting.

- Support fetching variables from leases and also updating and adding
  variables to leases via OMAPI.

- If two failover peers have wildly different clocks, refuse to start
  doing failover.

- Fix a bug in the DNS update code that could cause core dumps when
  running on alpha processors.

- Fixed a bug in ddns updates for static lease entries, thanks to a
  patch from Andrey M Linkevitch.

- Add support for Darwin/MacOS X

- Install omshell (including new documentation).

- Support DNS updates in the client (this is a very obscure feature
  that most DHCP client users probably will not be able to use).

- Somewhat cleaner status logging in the client.

- Make OMAPI key naming syntax compatible with the way keys are
  actually named (key names are domain names).

- Fix a bug in the lease file writer.

- Install DHCP ISC headers in a different place than BIND 9 ISC
  headers, to avoid causing trouble in BIND 9 builds.

- Don't send updates for attributes on an object when the attributes
  haven't changed.   Support deleting attributes on remote objects.

- Fix a number of bugs in omshell, and add the unset and refresh
  statements.

- Handle disconnects in OMAPI a little bit more intelligently (so that
  the caller gets ECONNRESET instead of EINVAL).

- Fix a bunch of bugs in the handling of clients that have existing
  leases when the try to renew their leases while failover is
  operating.

		Changes since 3.0 Release Candidate 3

- Do lease billing on startup in a way that I *think* will finally do
  the billing correctly - the previous method could overbill as a
  result of duplicate leases.

- Document OMAPI server objects.

	  Changes since 3.0 Release Candidate 2 Patchlevel 1

- Fix some problems in the DDNS update code.   Thanks to Albert
  Herranz for figuring out the main problem.

- Fix some reference counting errors on host entries that were causing
  core dumps.

- Fix a byte-swap bug in the token ring code, thanks to Jochen
  Friedrich.

- Fix a bug in lease billing, thanks to Jonas Bulow.

		Changes since 3.0 Release Candidate 2

- Change the conditions under which a DHCPRELEASE is actually
  committed to be consistent with lease binding states rather than
  using the lease end time.   THis may fix some problems with the
  billing class code.

- Fix a bug where lease updates would fail on Digital Unix (and maybe
  others) because malloc was called with a size of zero.

- Fix a core dump that happens when the DHCP server can't create its
  trace file.

	  Changes since 3.0 Release Candidate 1 Patchlevel 1

- Fix the dhcp_failover_put_message to not attempt to allocate a
  zero-length buffer.   Some versions of malloc() fail if you try to
  allocate a zero-length buffer, and this was causing problems on,
  e.g., Digital Unix.

- Fix a case where the failover code was printing an error message
  when no error had occurred.

- Fix a problem where when a server went down and back up again, the
  peer would not see a state transition and so would stay in the
  non-communicating state.

- Be smart about going into recover_wait.

- Fix a problem in the failover implementation where peers would fail
  to come into sync if interrupted in the RECOVER state.   This could
  have been the cause of some problems people have reported recently.

- Fix a problem with billing classes where they would not be unbilled
  when the client lease expired.

- If select fails, figure out which descriptor is bad, and cut it out
  of the I/O loop.   This prevents a potentially nasty spin.  I
  haven't heard any report it in a while, but it came up consistently
  in testing.

- Fix a bug in the relay agent where if you specified interfaces on
  the command line, it would fail.

- Fix a couple of small bugs in the omapi connection object (no known
  user impact).

- Add the missing 3.0 Beta 1 lease conversion script.

- Read dhcp client script hooks if they exist, rather than only if
  they're executable.

		Changes since 3.0 Release Candidate 1

- Fix a memory smash that happens when fixed-address leases are used.
  ANY SITE AT WHICH FIXED-ADDRESS STATEMENTS ARE BEING USED SHOULD
  UPGRADE IMMEDIATELY.   This has been a long-standing bug - thanks to
  Alvise Nobile for discovering it and helping me to find it!

- Fix a small bug in binary-to-ascii, thanks to H. Peter Anvin of
  Transmeta.

- There is a known problem with the DHCP server doing failover on
  Compaq Alpha systems.   This patchlevel is not a release candidate
  because of this bug.   The bug should be straightforward to fix, so
  a new release candidate is expected shortly.

- There is a known problem in the DDNS update code that is probably a
  bug, and is not, as far as we know, fixed in this patchlevel.

		Changes since 3.0 Beta 2 Patchlevel 24

- Went over problematic failover state transitions and made them all
  work, so that failover should now much less fragile.

- Add some dhcpctl and omapi documentation

- Fix compile errors when compiling with unusual predefines.

- Make Token Ring work on Linux 2.4

- Fix the Digital Unix BPF_WORDALIGN bug.

- Fix some dhcp client documentation errors.

- Update some parts of the README file.

- Support GCC on SCO.

	        Changes since 3.0 Beta 2 Patchlevel 23

- Fix a bug in the DNS update code where a status code was not being
  checked.   This may have been causing core dumps.

- When parsing the lease file, if a lease declaration includes a
  billing class statement, and the lease already has a billing class,
  unbill the old class.

- When processing failover transactions, where acks will be deferred,
  process the state transition immediately.

-  Don't try to use the new SIOCGIFCONF buffer size detection code on
   Linux 2.0, which doesn't provide this functionality.

- Apply a patch suggested by Tuan Uong for a problem in dlpi.c.

- Fix a problem in using the which command in the configure script.

- Fix a parse error in the client when setting up an omapi listener.

- Document the -n and -g flags to the client.

- Make sure there is always a stdin and stdout on startup.   This
  prevents shell scripts from accidentally writing error messages into
  configuration files that happen to be opened as stderr.

- If an interface is removed, the client will now notice that it is
  gone rather than spinning.   This has only been tested on NetBSD.

- The client will attempt to get an address even if it can't create a
  lease file.

- Don't overwrite tracefiles.

- Fix some memory allocation bugs in failover.

	        Changes since 3.0 Beta 2 Patchlevel 22

- Apply some patches suggested by Cyrille Lefevre, who is maintaining
  the FreeBSD ISC DHCP Distribution port.

- Fix a core dump in DHCPRELEASE.

	        Changes since 3.0 Beta 2 Patchlevel 21

- This time for sure: fix the spin described in the changes for pl20.

	        Changes since 3.0 Beta 2 Patchlevel 20

- Fix a problem with Linux detecting large numbers of interfaces (Ben)

- Fix a memory smash in the quotify code, which was introduced in
  pl19.

- Actually fix the spin described in the changes for pl20.   The
  previous fix only partially fixed the problem - enough to get it
  past the regression test.

	        Changes since 3.0 Beta 2 Patchlevel 19

- Fix a bug that could cause the server to abort if compiled with
  POINTER_DEBUG enabled.

- Fix a bug that could cause the server to spin when responding to a
  DHCPREQUEST.

- Apply Joost Mulders' suggested patches for DLPI on x86.

- Support NUL characters in quoted strings.

- Install unformatted man pages on SunOS.

	        Changes since 3.0 Beta 2 Patchlevel 18

- Allow the server to be placed in partner-down state using OMAPI.
  (Damien Neil)

- Implement omshell, which can be used to do arbitrary things to the
  server (in theory). (Damien Neil)

- Fix a case where if a client had two different leases the server could
  actually dereference the second one when it hadn't been referenced,
  leading to memory corruption and a core dump. (James Brister)

- Fix a case where a client could request the address of another client's
  lease, but find_lease wouldn't detect that the other client had it, and
  would attempt to allocate it to the client, resulting in a lease conflict
  message.

- Fix a case where a client with more than one client identifier could be
  given a lease where the hardware address was correct but the client
  identifier was not, resulting in a lease conflict message.

- Fix a problem where the server could write out a colon-seperated
  hex list as a value for a variable, which would then not parse.
  The fix is to always write strings as quoted strings, with any
  non-printable characters quoted as octal escape sequences.   So
  a file written the old way still won't work, but new files written
  this way will work.

- Fix documentation for sending non-standard options.

- Use unparsable names for unknown options.    WARNING: this will
  break any configuration files that use the option-nnn convention.
  If you want to continue to use this convention for some options,
  please be sure to write a definition, like this:

  option option-nnn code nnn = string;

  You can use a descriptive name instead of option-nnn if you like.

- Fix a problem where we would see a DHCPDISCOVER/DHCPOFFER/
  DHCPREQUEST/DHCPACK/DHCPREQUEST/DHCPNAK sequence.   This was the
  result of a deceptively silly bug in supersede_lease.

- Fix client script exit status check, according to a fix supplied by
  Hermann Lauer.

- Fix an endianness bug in the tracefile support, regarding ICMP
  messages.

- Fix a bug in the client where the medium would not work correctly if
  it contained quoted strings.

		       ** there was no pl17 **

	        Changes since 3.0 Beta 2 Patchlevel 16

- Add support for transaction tracing.   This allows the state of the
  DHCP server on startup, and all the subsequent transactions, to be
  recorded in a file which can then be played back to reproduce the
  behaviour of the DHCP server.   This can be used to quickly
  reproduce bugs that cause core dumps or corruption, and also for
  tracking down memory leaks.

- Incorporate some bug fixes provided by Joost Mulders for the DLPI
  package which should clear up problems people have been seeing on
  Solaris.

- Fix bugs in the handling of options stored as linked lists (agent
  options, fqdn options and nwip options) that could cause memory
  corruption and core dumps.

- Fix a bug in DHCPREQUEST handling that resulted in DHCPNAK messages
  not being send in some cases when they were needed.

- Make the lease structure somewhat more compact.

- Make initial failover startup *much* faster.   This was researched
  and implemented by Damien Neil.

- Add a --version flag to all executables, which prints the program
  name and version to standard output.

- Don't rewrite the lease file every thousand leases.

- A bug in nit.c for older SunOS machines was fixed by a patch sent in
  by Takeshi Hagiwara.

- Fix a memory corruption bug in the DHCP client.

- Lots of documentation updates.

- Add a feature allowing environment variables to be passed to the
  DHCP client script on the DHCP client command line.

- Fix client medium support, which had been broken for some time.

- Fix a bug in the DHCP client initial startup backoff interval, which
  would cause two DHCPDISCOVERS to be sent back-to-back on startup.


	        Changes since 3.0 Beta 2 Patchlevel 15

- Some documentation tweaks.

- Maybe fix a problem in the DLPI code.

- Fix some error code space inconsistencies in ddns update code.

- Support relay agents that intercept unicast DHCP messages to stuff
  agent options into them.

- Fix a small memory leak in the relay agent option support code.

- Fix a core dump that would occur if a packet was sent with no
  options.

	        Changes since 3.0 Beta 2 Patchlevel 14

- Finish fixing a long-standing bug in the agent options code.   This
  was causing core dumps and failing to operate correctly - in
  particular, agent option stashing wasn't working.   Agent option
  stashing should now be working, meaning that agent options can be
  used in class statements to control address allocation.

- Fix up documentation.

- Fix a couple of small memory leaks that would have added up
  significantly in a high-demand situation.

- Add a log-facility configuration parameter.

- Fix a compile error on some older operating systems.

- Add the ability in the client to execute certain statements before
  transmitting packets to the server.   Handy for debugging; not much
  practical use otherwise.

- Don't send faked-out giaddr when renewing or bound - again, useful
  for debugging.

	        Changes since 3.0 Beta 2 Patchlevel 13

- Fixed a problem where the fqdn decoder would sometimes try to store
  an option with an (unsigned) negative length, resulting in a core
  dump on some systems.

- Work around the Win98 DHCP client, which NUL-terminates the FQDN
  option.

- Work around Win98 and Win2k clients that will claim they want to do
  the update even when they don't have any way to do it.

- Fix some log messages that can be printed when failover is operating
  that were not printing enough information.

- It was possible for a DHCPDISCOVER to get an allocation even when
  the state machine said the server shouldn't be responding.

- Don't load balance DHCPREQUESTs from clients in RENEWING and
  REBINDING, since in RENEWING, if we heard it, it's for us, and in
  REBINDING, the client wouldn't have got to REBINDING if its primary
  were answering.

- When we get a bogus state lease binding state transition, don't do
  the transition.
  

	        Changes since 3.0 Beta 2 Patchlevel 12

- Fixed a couple of silly compile errors.

		Changes since 3.0 Beta 2 Patchlevel 11

- Albert Herranz tracked down and fixed a subtle bug in the base64
  decoder that would prevent any key with an 'x' in its base64
  representation from working correctly.

- Thanks to Chris Cheney and Michael Sanders, we have a fix for the
  hang that they both spotted in the DHCP server - when
  one-lease-per-client was set, the code to release the "other" lease
  could spin.

- Fix a problem with alignment of the input buffer in bpf in cases
  where two packets arrive in the same bpf read.

- Fix a problem where the relay agent would crash if you specified an
  interface name on the command line.

- Add the ability to conditionalize client behaviour based on the
  client state.

- Add support for the FQDN option, and added support for a new way of
  doing ddns updates (ddns update style interim) that allows more than
  one DHCP server to update the DNS for the same network(s).   This
  was implemented by Damien Neil with some additional functionality
  added by Ted Lemon.

- Damien added a "log" statement, so that the configuration file can
  be made to log debugging information and other information.

- Fixed a bug that caused option buffers not to be terminated with an
  end option.

- Fixed a long-standing bug in the support for option spaces where the
  options are stored as an ordered list rather than in a hash table,
  which could theoretically result in memory pool corruption.

- Prevent hardware declarations with no actual hardware address from
  being written as something unparsable, and behave correctly in the
  face of a null hardware address on input.

- Allow key names to be FQDNs, and qualify the algorithm name if it is
  specified unqualified.

- Modify the DDNS update code so that it never prints the "resolver
  failed" message, but instead says *why* the resolver failed.

- Officially support the subnet selection option, which now has an
  RFC.

- Fix a build bug on MacOS X.

- Allow administrator to disable ping checking.

- Clean up dhcpd.conf documentation and add more information about how
  it works.

		Changes since 3.0 Beta 2 Patchlevel 10

- Fix a bug introduced during debugging (!) and accidentally committed
  to CVS.

		Changes since 3.0 Beta 2 Patchlevel 9

- Fix DHCP client handling of vendor encapsulated options.

- Fix a bug in the handling of relay agent information options introduced
  in patchlevel 9.

- Stash agent options on client leases by default, and use the stashed
  options at renewal time.

- Add the ability to test the client's binding state in the client
  configuration language.

- Fix a core dump in the DNS update code.

- Fix some expression evaluation bugs that were causing updates to be
  done when no client hostname was received.

- Fix expression evaluation debugging printfs.

- Teach pretty_print_option to print options in option spaces other than
  the DHCP option space.

- Add a warning message if the RHS of a not is not boolean.

- Never select for more than a day, because some implementations of
  select will just fail if the timeout is too long (!).

- Fix a case where a DHCPDISCOVER from an unknown network would be
  silently dropped.

- Fix a bug where if a client requested an IP address for which a different
  client had the lease, the DHCP server would reallocate it anyway.

- Fix the DNS update code so that if the client changes its name, the DNS
  will be correctly updated.

		Changes since 3.0 Beta 2 Patchlevel 8

- Oops, there was another subtle math error in the header-length
  bounds-checking.

		Changes since 3.0 Beta 2 Patchlevel 7

- Oops, forgot to byte-swap udp header length before bounds-checking it.

		Changes since 3.0 Beta 2 Patchlevel 6

- Fix a possible DoS attack where a client could cause the checksummer
  to dump core.   This was a read, not a write, so it shouldn't be
  possible to exploit it any further than that.

- Implement client- and server-side support for using the Client FQDN
  option.

- Support for other option spaces in the client has been added.   This
  means that it is now possible to define a vendor option space on the
  client, request options in that space from the server (which must
  define the same option space), and then use those options in the
  client.   This also allows NWIP and Client FQDN options to be used
  meaningfully.

- Add object initializer support.   This means that objects can now be
  initialized to something other than all-zeros when allocated, which
  makes, e.g., the interface object support code a little more robust.

- Fix an off-by-one bug in the host stuffer.   This was causing host
  deletes not the work, and may also have been causing OMAPI
  connections to get dropped.   Thanks to James Brister for tracking
  this one down!

- Fixed a core dump in the interface discovery code that is triggered
  when there is no subnet declaration for an interface, but the server
  decides to continue running.   Thanks to Shane Kerr for tracking
  down and fixing this problem.

		Changes since 3.0 Beta 2 Patchlevel 5

- Fix a bug in the recent enhancement to the interface discovery code
  to support arbitrary-length interface lists.

- Support NUL-terminated DHCP options when initializing client-script
  environment.

- Fix suffix operator.

- Fix NetWare/IP option parsing.

- Better error/status checking in dhcpctl initialization and omapi
  connection code.

- Fix a potential memory smash in dhcpctl code.

- Fix SunOS4 and (maybe) Ultrix builds.

- Fix a bug where a certain sort of incoming packet could cause a core
  dump on Solaris (and probably elsewhere).

- Add some more safety checks in error logging code.

- Add support for ISC_R_INCOMPLETE in OMAPI protocol connection code.

- Fix relay agent so that if an interface is specified on the command
  line, the relay agent does not dump core.

- Fix class matching so that match if can be combined with match or
  spawn with.

- Do not allow spurious leases in the lease database to introduce
  potentially bogus leases into the in-memory database.

- Fix a byte-order problem in the client hardware address type code
  for OMAPI.

- Be slightly less picky about what sort of hardware addresses OMAPI
  can install in host declarations.

		Changes since 3.0 Beta 2 Patchlevel 4

- Incorporated Peter Marschall's proposed change to array/record
  parsing, which allows things like the slp-agent option to be encoded
  correctly.   Thanks very much to Peter for taking the initiative to
  do this, and for doing such a careful job of it (e.g., updating the
  comments)!

- Added an encoding for the slp-agent option.   :')

- Fixed SunOS 4 build.  Thanks to Robert Elz for responding to my
  request for help on this with patches!

- Incorporated a change that should fix a problem reported by Philippe
  Jumelle where when the network connection between two servers is
  lost, they never reconnect.

- Fix client script files other than that for NetBSD to actually use
  make_resolv_conf as documented in the manual page.

- Fix a bug in the packet handling code that could result in a core
  dump.

- Fix a bug in the bootp code where responses on the local net would
  be sent to the wrong MAC address.   Thanks to Jerry Schave for
  catching this one.

		Changes since 3.0 Beta 2 Patchlevel 3

- In the DHCP client, execute client statements prior to using the values
  of options, so that the client configuration can overried, e.g., the
  lease renewal time.

- Fix a reference counting error that would result in very reproducible
  failures in updates, as well as occasional core dumps, if a zone was
  declared without a key.

- Fix some Linux 2.0 compilation problems.

- Fix a bug in scope evaluation during execution of "on" statements that
  caused values not to be recorded on leases.

- If the dhcp-max-message-size option is specified in scope, and the
  client didn't send this option, use the one specified in scope to
  determine the maximum size of the response.

		Changes since 3.0 Beta 2 Patchlevel 2

- Fix a case where spawning subclasses were being allocated
  incorrectly, resulting in a core dump.

- Fix a case where the DHCP server might inappropriately NAK a
  RENEWING client.

- Fix a place dhcprequest() where static leases could leak.

- Include memory.h in omapip_p.h so that we don't get warnings about
  using memcmp().

		Changes since 3.0 Beta 2 Patchlevel 1

- Notice when SIOCFIGCONF returns more data than fit in the buffer -
  allocate a larger buffer, and retry.   Thanks to Greg Fausak for
  pointing this out.

- In the server, if no interfaces were configured, report an error and
  exit.

- Don't ever record a state of 'startup'.

- Don't try to evaluate the local failover binding address if none was
  specified.   Thanks to Joseph Breu for finding this.