OPNsense

OPNsense is an open source firewall and routing platform built on FreeBSD. It runs as a network appliance with a web interface and an API, giving home and business networks stateful packet filtering for IPv4 and IPv6 along with a live view of passed and blocked traffic.

Beyond filtering, it handles multi-WAN setups with load balancing and failover, and built-in VPN support for IPsec, OpenVPN, and WireGuard. Inline intrusion detection and prevention is provided through Suricata, and a captive portal, traffic shaping, and proxy features are included. Reporting covers RRD graphs and NetFlow analysis.

High availability is supported through CARP-based hardware failover with state synchronization. OPNsense is released under the 2-clause BSD license and is developed in the open with a large user community.