What is OpenVPN® protocol?

OpenVPN® is one of the youngest, since it was released in 2001, and widely used open-source technology, i.e. everyone can freely use it and modify it as needed. It uses a custom security protocol that utilizes SSL/TLS for key exchange, creating secure point-to-point or site-to-site connections. OpenVPN® can run over User Datagram Protocol (UDP) or Transmission Control Protocol (TCP) tunnel transports. This makes your web traffic indistinguishable from the traffic using standard HTTPS over SSL, and it is therefore extremely difficult to detect and block.

The TCP port provides reliable, ordered, and error-checked end-to-end delivery of a stream of information packets between distinct nodes. It is one of the most used protocols in digital network communications, and one of the main part of the Internet protocol suite, commonly known as TCP/IP. In this collaboration, IP defines the logical location of the remote node, while TCP creates a connection, breaks large data into smaller packets, and ensures that they are delivered to the correct destination. Applications that require a reliable data stream service are recommended to use this connection-oriented protocol.

The UDP port is a simple OSI transport layer protocol for network applications based on Internet Protocol (IP). UDP is the main alternative to TCP and one of the oldest network protocols, introduced in 1980. UDP is an ideal protocol for network applications in which perceived latency is critical such as gaming, voice, and video communications. The protocol permits individual packets to be dropped and UDP packets to be received in a different order than that in which they were sent, allowing for better performance.

VPN Unlimited® supports OpenVPN® both via the TCP and UDP ports.

Features and technical details

Due to its strong features, ease of use, and extensive support, OpenVPN® became one of the most popular VPN software solutions. Here are more characteristics of the protocol:

  • High level of security and configurability
  • Use of up to 256 bit encryption
  • Support for dynamic IP addresses and DHCP
  • Scalability to hundreds or thousands of users
  • Portability to most major OS platforms through third party software
  • No support for IPSec, L2TP and PPTP

VPN Unlimited® uses OpenVPN® as a default protocol for Windows, Android, and Linux. To increase security on your iOS devices, we recommend you to enable our special technology, called KeepSolid Wise that operates via the UDP and TCP ports as well.


  • Extremely secure
  • Goes through firewalls
  • Open source
  • Uses a wide range of encryption algorithms
  • Highly configurable


  • Uses third party software
  • Support on mobile devices needs improvements
  • Requires technical knowledge to configure

“OpenVPN” is a registered trademark of OpenVPN Inc.