Pfsence
Redundancy
CARP from OpenBSD allows for hardware failover. 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. pfSense also includes configuration synchronization capabilities, so you make your configuration changes on the primary and they automatically synchronize to the secondary firewall.
pfsync ensures 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
Load Balancing
Outbound Load Balancing
Outbound load balancing is used with multiple WAN connections to provide load balancing and failover capabilities. Traffic is directed to the desired gateway or load balancing pool on a per-firewall rule basis.
Inbound Load Balancing
Inbound load balancing is used to distribute load between multiple servers. This is commonly used with web servers, mail servers, and others. Servers that fail to respond to ping requests or TCP port connections are removed from the pool.
