Log Message:
Update ISC DHCP related pacakges to 4.2.0.

			Changes since 4.2.0 (new features)

- If a client renews before 'dhcp-cache-threshold' percent of its lease
  has elapsed (default 25%), the server will reuse the allocated lease
  (provide a lease within the currently allocated lease-time) rather
  than extend or renew the lease.  This absolves the server of needing
  to perform an fsync() operation on the lease database before reply,
  which improves performance. [ISC-Bugs #22228]
  Updated this patch to support asynchronous DDNS.  If the server is
  attempting to do DDNS on a lease it should be udpated and written to
  disk even if that wouldn't be necessary due to the thresholding.
  [ISC-Bugs #26311]

- The 'no available billing' log line now also logs the name of the last
  matching billing class tried before failing to provide a billing.
  [ISC-Bugs #21759]

- A problem with missing get_hw_addr function when --enable-use-sockets
  was used is now solved on GNU/Linux, BSD and GNU/Hurd systems. Note
  that use-sockets feature was not tested on those systems. Client and
  server code no longer use MAX_PATH constant that is not defined on
  GNU/Hurd systems. [ISC-Bugs #25979]

- Add a perl script in the contrib directory, dhcp-lease-list.pl, which
  can parse v4 lease files and output the lease information in a more
  human friendly manner.  This was written by Christian Hammers with
  some updates by vom and ISC.  This is contributed code and is not
  supported by ISC; however it may be useful to some users.
  [ISC-Bugs #20680]

- Add support in v6 for on-commit, on-expire and on-release.
  [ISC-Bugs #27912]

- Add support for using classes with v6.
  [ISC-Bugs #26510]

- Update the DDNS code to current standards and allow for sharing
  of DDNS entries between v4 and v6 clients.  The new code is used
  if the ddns-update-style is set to "standard", the older code is
  still available if ddns-update-style is set to "interim".  The
  oldest DDNS code "ad-hoc" has been removed.  Thanks to Thomas Pegeot
  who submitted a patch for this issue.  This patch is based on
  that work with some modifications.
  [ISC-Bugs #21139]

- Add a configuration option to the server to suppress using fsync().
  Enabling this option will mean that fsync() is never called.  This
  may provide better performance but there is also a risk that a lease
  will not be properly written to the disk after it has been issued
  to a client and before the server stops.  Using this option is
  not recommended.
  [ISC-Bugs #34810]

- Add some logging statements to indicate when the server is ready
  to serve.  One statement is emitted after the server has finished
  reading its files and is about to enter the dispatch loop.
  This is "Server starting service.".
  The second is emitted when a server determines that both it and
  its failover peer are in the normal state.
  This is "failover peer <name>: Both servers normal."
  [ISC-Bugs #33208]

- Add support for accessing options from v6 relays.  The v6relay
  statement allows the administrator to choose which relay to
  use when searching for an option, see the dhcp-options man page
  for a description.  The host-identifier option has also been
  updated to support the use of relay options, see the dhcpd.conf
  man page for a description.
  [ISC-Bugs #19598]

- When doing DDNS if there isn't an appropriate zone statement attempt
  to find a reasonable nameserver via a DNS resolver.  This restores
  some functionality that was lost in the transition to asynchronous
  DDNS.  Due to the lack of security and increase in fragility of the
  system when using this feature we strongly recommend the use of
  appropriate zone statements rather than using this functionality.
  [ISC-Bugs #30461]

- Add support for specifying the address from which to send
  DDNS updates on the DHCP server.  There are two new options
  "ddns-local-address4" and "ddns-local-address6" that each take
  one instance of their respective address types.
  [ISC-Bugs #34779]

- Add ignore-client-uids option in the server.  This option causes
  the server to not record a client's uid in its lease.  This
  violates the specification but may also be useful when a client
  can dual boot using different client ids but the same mac address.
  Thank you to Brian De Wolf at Cal Poly Pomona for the patch.
  [ISC-Bugs #32427]
  [ISC-Bugs #35066]

- Extend the DHCPINFORM processing to honor the subnet selection option
  and take host declarations into account.
  Thanks to Christof Chen for testing and submitting the patch.
  [ISC-Bugs #35015]

- Extend the hardware expression to look into the lease structure
  for a hardware address if there is no packet.  This allows the
  server to find the hardware address during on-expiry processing.
  [ISC-Bugs #24584]

- Add definitions for some options that have been specified by the IETF.
  [ISC-Bugs #29268]
  [ISC-Bugs #35198]

			Changes since 4.3.0b1

- Tidy up receive packet processing.
  Thanks to Brad Plank of GTA for reporting the issue and suggesting
  a possible patch.
  [ISC-Bugs #34447]

			Changes since 4.3.0a1

- Modify the message displayed when a process hits a fatal error.
  The new message is much shorter and simply points to the README
  and our website for directions on bug submissions.
  [ISC-Bugs #24789]

- Handle an absent resolv.conf file better.
  [ISC-Bugs #35194]