LANfacing

LANfacing is a term used in networking to describe the side of a device that faces the local area network. It is commonly paired with WAN-facing or Internet-facing to describe the two broad interfaces of edge devices such as routers, firewalls, or gateways.

A LANfacing interface is connected to the internal network and carries traffic to and from devices within the LAN. In typical deployments, traffic destined for external networks exits through the WAN-facing side, while internal hosts route through the LANfacing side.

Many devices use multiple LANfacing interfaces or subinterfaces associated with different VLANs to segment traffic and enforce security zones. IP addressing and routing are configured on LANfacing interfaces, and inter-LAN routing is performed by the device.

Security and management practices often treat LANfacing interfaces as trusted surfaces. Access to configuration and monitoring is restricted to dedicated management networks or out-of-band connections, and firewall rules, NAT, and access control lists regulate traffic between LANfacing networks.

In cloud, virtualized, or home environments, the LANfacing side may connect to the user devices and internal services, while the exterior or Internet connection remains WANfacing. Understanding LANfacing helps in designing segmentation, policy enforcement, and troubleshooting.