pfSense / OPNsense

Full-featured open-source firewall/router appliances (FreeBSD-based) with NAT, VPN, and firewall rules in one web UI. Most-used open-source alternative for the router role behind NAT_Gateway and Internet_Gateway; a bare-bones self-managed NAT instance running iptables/nftables covers the same NAT function with more manual setup and no UI.

Related

• NAT_Gateway
• Internet_Gateway
• AWS_Network_Firewall