Update isc-dhcp4 package to 4.2.2 and it also update isc-dhcpd4, isc-dhclient4
and isc-dhcrelay4.  Here is quote from DHCP 4.2.2 Release Notes.
(http://ftp.isc.org/isc/dhcp/dhcp-4.2.2-RELNOTES)

	      Internet Systems Consortium DHCP Distribution
			     Version 4.2.2
			      27 July 2011

			      Release Notes

			      NEW FEATURES

ISC DHCP 4.2.x includes features that were not included in DHCP 4.1.x.
These include:

Processing the DHCP to DNS server transactions in an asynchronous fashion.
The DHCP server or client can now continue with it's processing while
awaiting replies from the DNS server.

There are a number of DHCPv6 limitations and features missing in this
release, which will be addressed in the future:

- Only Solaris, Linux, FreeBSD, NetBSD, and OpenBSD are supported.

- DHCPv6 includes human-readable text in status code messages, in
  English.  A method to reconfigure or support other languages would
  be preferable.

- The "host-identifier" option is limited to a simple token.

- The client and server can only operate DHCPv4 or DHCPv6 at a time,
  not both.  To use both protocols simultaneously, two instances of the
  relevant daemon are required, one with the '-6' command line option.

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.

ISC DHCP uses standard GNU configure for installation. Please review the
output of "./configure --help" to see what options are available.

The system has only been tested on Linux, FreeBSD, and Solaris, and may not
work on other platforms. Please report any problems and suggested fixes to
<dhcp-users@isc.org>.

			Changes since 4.2.2rc1

! Two packets were found that cause a server to halt.  The code
  has been updated to properly process or reject the packets as
  appropriate.  Thanks to David Zych at University of Illinois
  for reporting this issue.  [ISC-Bugs #24960]
  One CVE number for each class of packet.
  CVE-2011-2748
  CVE-2011-2749

			Changes since 4.2.2b1

- Strict checks for content of domain-name DHCPv4 option can now be
  configured during compilation time. Even though RFC2132 does not allow
  to store more than one domain in domain-name option, such behavior is
  now enabled by default, but this may change some time in the future.
  See ACCEPT_LIST_IN_DOMAIN_NAME define in includes/site.h.
  [ISC-Bugs #24167]

- DNS Update fix. A misconfigured server could crash during DNS update
  processing if the configuration included overlapping pools or
  multiple fixed-address entries for a single address.  This issue
  affected both IPv4 and IPv6. The fix allows a server to detect such
  conditions, provides the user with extra information and recommended
  steps to fix the problem.  If the user enables the appropriate option
  in site.h then server will be terminated
  [ISC-Bugs #23595]


(taca)