Where OpenVPN came from
OpenVPN was written by James Yonan in 2001, at a time when commercial VPN software was largely closed-source and enterprise IPsec deployments had a reputation for being difficult to configure correctly — a single misconfigured setting could silently weaken an entire tunnel. Yonan built OpenVPN as an open-source alternative, releasing the source code so it could be reviewed, audited, and improved by anyone rather than trusted on a vendor's word.
That decision turned out to matter more than speed or convenience. Because OpenVPN's code has been public for over twenty years, it has been formally security-audited multiple times, including a widely cited 2017 audit funded by the Open Source Technology Improvement Fund. Few VPN protocols have been scrutinized this thoroughly for this long.
How it actually works
OpenVPN builds its security on TLS — the same protocol family that secures HTTPS websites — using the OpenSSL library for its cryptographic operations. This gives it a level of configurability that few other VPN protocols match: administrators can choose ciphers, authentication methods, and key exchange algorithms, and the protocol can run over either UDP (faster, preferred for most uses) or TCP (more reliable through restrictive networks, though slower).
That TCP fallback is one reason OpenVPN became a favorite in unstable or heavily restricted network environments: because it can run over port 443 — the same port used by every HTTPS website — a censor trying to block it risks blocking a large portion of the ordinary web along with it.
OpenVPN runs entirely in userspace, which means every packet has to cross between kernel and application memory space — real overhead that protocols like WireGuard, running partly in the kernel, don't pay. OpenVPN is also older and more configurable, which is a double-edged sword: flexible, but easier to misconfigure than a protocol with fewer knobs.
OpenVPN vs. WireGuard
| Property | OpenVPN | WireGuard |
|---|---|---|
| Released | 2001 | 2016 |
| Cryptography | Configurable (OpenSSL) | Fixed modern suite |
| Transport | UDP or TCP | UDP only |
| Port 443 disguise | Yes, natively over TCP | Needs a wrapper |
| Audit history | Extensive, 20+ years | Growing, since 2016 |
Where you'll encounter it
OpenVPN remains a default option in nearly every consumer and enterprise VPN client, and it's often the recommended fallback in networks where WireGuard's distinctive traffic pattern gets blocked outright. Its ability to blend into port 443 traffic still makes it relevant in restrictive network environments where newer, faster protocols sometimes get filtered first.
MiTiVPN keeps OpenVPN available as a compatibility fallback for exactly this reason — networks and devices that can't or won't run WireGuard or VLESS-based tunnels still have a thoroughly audited, TCP-443-capable option.