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OpenVPN

OpenVPN is a popular open-source VPN protocol that creates a secure, encrypted tunnel between your device and a server. It is trusted for being highly secure, configurable, and widely supported.

Last updated June 8, 2026

Definition

OpenVPN is an open-source VPN protocol and software that establishes a secure, encrypted tunnel between a client and a server. Released in 2001, it has become an industry standard thanks to its strong security, transparency, and broad platform support.

How OpenVPN works

OpenVPN uses the OpenSSL library and the SSL/TLS protocol to handle encryption and key exchange. It can run over two transport modes: UDP for speed and TCP for reliability and easier firewall traversal (often on port 443 to look like normal HTTPS). The tunnel encrypts all traffic so your ISP and intermediaries cannot read it.

Why it matters

Because the code is open source, OpenVPN has been heavily audited, making it one of the most trusted protocols for privacy. It supports a wide range of ciphers and is highly configurable, which suits both consumer VPNs and enterprise deployments.

  • Open source: publicly auditable code.
  • Flexible: UDP or TCP, many cipher options.
  • Trade-off: slower and heavier than modern protocols like WireGuard.

It remains a reliable choice where compatibility and proven security matter most.

Examples

1

A consumer VPN app offering OpenVPN UDP and TCP connection options

2

Running OpenVPN over TCP port 443 to bypass a restrictive firewall

3

A company deploying OpenVPN Access Server for remote employee access

Common Use Cases

Securing remote access for businesses and remote workers
Encrypting traffic on untrusted public Wi-Fi
Bypassing firewalls using TCP port 443 to mimic HTTPS
Building self-hosted VPN servers with full configuration control

Frequently Asked Questions

Yes, OpenVPN is considered very secure. Its open-source code has been extensively audited and it supports strong ciphers like AES-256 via OpenSSL.
OpenVPN is more battle-tested and flexible, but WireGuard is faster and lighter. The best choice depends on whether you prioritize speed or maximum configurability.
Use UDP for better speed in most cases, and switch to TCP when you need reliability or must bypass firewalls that block UDP.

Keep Learning

All terms

SOCKS5

SOCKS5 is the latest version of the SOCKS proxy protocol. It routes any kind of network traffic — TCP and UDP — between a client and a server through a proxy, with optional authentication and no awareness of the underlying application.

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VPN

A VPN (Virtual Private Network) encrypts all of your device's internet traffic and routes it through a remote server, hiding your IP and protecting data on untrusted networks.

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SSL/TLS

SSL/TLS is the encryption protocol that secures data in transit on the web — the 'S' in HTTPS — protecting it from eavesdropping and tampering.

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WireGuard

WireGuard is a modern, fast and lightweight VPN protocol known for its tiny codebase, strong cryptography and excellent performance.

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