The combination of CARP, pfsync, and our configuration synchronization provides high availability functionality. Two or more firewalls can be configured as a failover group. If one interface fails on the primary or the primary goes offline entirely, the secondary becomes active. The pfSense software also includes configuration synchronization capabilities, so you make your configuration changes on the primary and they automatically synchronize to the secondary firewall.
The firewall's state table is replicated to all failover configured firewalls. This means your existing connections will be maintained in the case of failure, which is important to prevent network disruptions.
Limitations: Only works with static public IPs, does not work with stateful failover using DHCP, PPPoE, or PPTP type WANs.