OpenVPN is a VPN protocol. A VPN protocol, or a “tunneling protocol,” is the set of instructions your device uses to negotiate the secure encrypted connection that forms the network between your computer and another.
OpenVPN uses SSL/TLS to handle its key exchange, has no known vulnerabilities, supports Perfect Forward Secrecy, and is very stable. It also supports both UDP and TCP.
OpenVPN is widely considered to be one of the most secure VPN software solutions. It is also open-source, which means that anyone can verify its code or use it for free. You can read more about how OpenVPN compares to other VPN protocols on our blog post, Which VPN protocol is the best?
OpenVPN is available in all ProtonVPN apps.
- Windows: OpenVPN
- macOS: OpenVPN and IKEv2
- Android: OpenVPN and IKEv2
- iOS/iPadOS: OpenVPN and IKEv2
- Linux: OpenVPN
If you are encountering connections problems, it is often useful to change VPN protocols. Our Windows, macOS, Android, and iOS/iPadOS apps support Smart Protocol, an anti-censorship feature that intelligently probes networks to discover the best VPN protocol configuration required for optimal performance or to bypass censorship.
For example, it can automatically switch from IKEv2 to OpenVPN, or OpenVPN UDP to OpenVPN TCP, using different ports as required.