Product concerned: SNS 4.x
Last update: May 2020
High availability (HA) is a feature that provides service continuity during a hardware or firewall failure, by deploying a cluster of firewalls. In this architecture, the links that interconnect the LAN and WAN must be duplicated, as shown below:
To form the high availability cluster, both firewalls are connected with one or two control links on dedicated interfaces. The second link is optional but strongly recommended.
Firewalls in a cluster have the same configuration, and operate in active/passive mode. This means that only one firewall is active or running at any given time, and is the same firewall that manages all traffic that goes through the networks connected to the cluster.