HP ProCurve NAC 800, User Manual

Page: 405 / 591

DHCP Plug-in
Overview
13-3
The DHCP plug-in is a Microsoft DHCP plug-in that utilizes the Microsoft
DHCP Server Callout Application Programming Interface (API). Installed on
each DHCP server in your network, the plug-in processes or ignores DHCP
packets based on the end-user device Media Access Control (MAC) address.
NAC 800 tests endpoints that request access to the network and either assigns
a quarantined Internet Protocol (IP) address (failed), or adds the MAC address
of the end-user device as an authorized device (allowed) to the Access Control
List (ACL) on the appropriate DHCP server.
The following connection and communication actions apply:
■ If the connection between the DHCP server and the NAC 800 server
is lost and re-established, the existing ACL on the DHCP server is
discarded and NAC 800 re-transmits the entire ACL.
■
If the DHCP server cannot communicate with NAC 800 at any time,
the DHCP server goes in to an
allow all or deny all state, depending
on the
failopen
parameter setting in the
C:\WINDOWS\SYSTEM32\DHCP\
config.xml
file (true = allow all,
false = deny all).
■ NAC 800 attempts to connect to known DHCP servers on start-up, and
continuously attempts to connect at regular intervals indefinitely.