| Feature | App-level (VPN client) | System-level (firewall) | | --- | --- | --- | | How it works | VPN app blocks its own tunnel | Firewall rules block all non-VPN traffic | | Reliability | Good, but can fail if app crashes | Excellent, OS-level enforcement | | Torrent safety | Usually sufficient | Best-in-class | | Example | NordVPN, ExpressVPN | WireGuard + iptables, pfSense |
Many VPNs don’t block IPv6. If your ISP assigns an IPv6 address, and your VPN uses only IPv4, your torrent client may leak IPv6 traffic. kill switch torrent
Suddenly, your real IP address is exposed to everyone in the swarm—including your ISP and copyright trolls. | Feature | App-level (VPN client) | System-level