D-Link NetDefend DFL-210 User Manual page 290

11.1. Overview
Chapter 11. High Availability
D-Link HA will only operate between two D-Link Firewalls. As the internal operation of different
security gateway manufacturer's software is completely dissimilar, there is no common method
available to communicating state information to a dissimilar device.
It is also strongly recommended that the D-Link Firewalls used in cluster have identical
configurations. They must also have identical licenses which allow identical capabilities including
the ability to run in an HA cluster.
Extending Redundancy
Implementing an HA Cluster will eliminate one of the points of failure in a network. Routers,
switches and Internet connections can remain as potential points of failure and redundancy for these
should also be considered.
The following sections describe the High Availability feature in greater detail.
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