What Is VPN Passthrough?
VPN passthrough is a router feature that allows VPN traffic to pass through the router's NAT firewall to a VPN server. It lets devices on your home network create outgoing VPN connections without being blocked.
How VPN passthrough works
Home routers use NAT to share one public IP address among many devices. Some older VPN protocols do not survive this translation well, so routers add passthrough options that recognize the VPN traffic and forward it correctly instead of dropping it.
Why it exists
VPN passthrough was created for legacy protocols like PPTP, L2TP, and IPSec, which struggle with NAT. You will often see separate PPTP, L2TP, and IPSec passthrough toggles in a router's settings, usually enabled by default.
Do you still need it?
Modern VPNs mostly do not. Protocols like VLESS, VMESS, and Shadowsocks run over standard connections that pass through routers without any special settings, so passthrough is rarely something you have to think about anymore.
Troubleshooting a blocked VPN
If an older VPN will not connect, check that the matching passthrough option is enabled on your router. For app-based VPNs on modern protocols, a failed connection is more often about network restrictions than passthrough, so switching servers or protocols usually helps.
Skip the router tweaks: Veepen runs on VLESS, VMESS, and Shadowsocks, which connect through most networks without passthrough settings. Try it free on Android and Android TV.