Split tunneling: route only selected apps through the VPN

By default a VPN is a full tunnel: every packet from your device goes through the encrypted exit. Split tunneling changes that — you choose which traffic uses the tunnel and which stays on your ordinary connection. Two common flavours exist: app-based (route this app through the VPN, leave that one direct) and destination-based (route these IP ranges or sites through the VPN, everything else direct).

The appeal is practical. Keep a bank site or a latency-sensitive game on your fast local connection while a scraper or a geo-restricted service goes through the VPN. Or reach local network devices — a printer, a NAS — that a full tunnel would otherwise cut off. The cost is that any traffic outside the tunnel is not protected, which is a real trade-off, not a free lunch.

Split tunneling shines when full-tunnel is overkill or gets in the way: accessing local devices, keeping trusted high-bandwidth traffic (video calls, backups) off the VPN, running one app abroad while the rest stays home, or reducing load on a metered exit. WireGuard's AllowedIPs makes destination-based splitting trivial — it is literally the routing table for the tunnel — and many clients add per-app splitting on top.

The honest warning: anything outside the tunnel travels over your real IP with no protection. If you split by app, be certain the app you left out is not one that leaks something sensitive, and remember that a split tunnel weakens the "everything is hidden" guarantee of a full tunnel. Watch too for DNS leaks — DNS may go out the wrong path if not pinned. The s4m VPN supports both modes; use full tunnel when privacy is the priority and split only when you have a concrete reason and understand what stays exposed.