Definition
A router is a network device that forwards packets between networks. Home routers connect a single residential network to the wider internet via an ISP; commercial routers operate at every level of the internet's backbone. Modern home routers also handle Wi-Fi, NAT, basic firewalling, and increasingly DNS over HTTPS. Most household VPN configurations terminate at individual devices, but routers can also run VPN client software themselves.
VPN at the Router Level
Configuring a VPN client on the router protects every device behind it without per-device installation. Smart TVs, game consoles, IoT devices, and guests all benefit automatically. The router negotiates a single tunnel and routes the household's traffic through it. The trade-off is that all devices share the same exit IP, and switching VPN servers or disabling the VPN affects everyone at once. OpenVPN, WireGuard, and L2TP/IPSec can all run on routers with sufficient CPU; cheaper routers struggle with full-bandwidth encryption.
Compatible Firmware
Stock router firmware often does not support VPN clients. Open-source replacements (DD-WRT, OpenWrt, Tomato, Asuswrt-Merlin) add support. Some VPN providers sell pre-flashed routers; others provide configuration files for popular firmwares. WireGuard support on routers is now common because of its low overhead, making router-level VPNs much more practical than they were in the OpenVPN-only era.