Unless you’ve been living under a rock, then you’ve must have heard the name “OpenVPN” by now. So, what is it? And how does it work? Well, if you want to know answers to these questions, then read on as I’ve covered all the necessary details about OpenVPN in this article.

What is OpenVPN?

This secure and reliable VPN protocol (and also software) uses VPN techniques to secure client-server communication. Programmed by James Yonan, it’s one of the most popular VPN protocols among VPN users at the moment.

Launched in 2001, OpenVPN and SoftEther are the only open-source VPN protocols that also have their own open-source application.

How does it Work?

As mentioned above, this VPN protocol uses VPN techniques to secure client-server communication. This ensures a safe transfer of information between the client and the server. 

OpenVPN relies on OpenSSL for handling encryption and authentication processes, with the option to use either “User Datagram Protocol” or “Transmission Control Protocol” for transmission. Since it’s a custom security protocol, OpenVPN enables you to easily get past NAT and HTTP, which are security measures whose primary purpose is to control access to the internet.

If you don’t know what “Transmission Control Protocol” and “User Datagram Protocol” are, well, they are transport layer protocols and are used for the transmission of data on the internet. The transmission control protocol is more stable than UDP. It offers error correction features (when a network packet is sent, transmission control protocol waits for confirmation before sending it again or sending a new packet). User datagram protocol lacks this feature, making it a little less stable but much faster.

According to OpenVPN’s official website, it works best over user datagram protocol, which is why the OpenVPN Access Server first tries to establish UDP connections (most VPN providers offer OpenVPN over UDP by default). The server only tries to establish TCP connections if it fails in establishing UDP connections. 

Another thing, which distinguishes OpenVPN from other VPN protocols is that it’s open-source. Meaning that third parties can contribute to it and help make it better.

Technical Details

Here are a few pointers to shed some light on some of the technical aspects of the service:

  • OpenVPN operates mostly under a 256-bit OpenSSL encryption. It can use 3DES, AES, Blowfish ciphers and strengthen the connection’s security further.
  • OpenVPN relies on its own custom protocol based on TLS and SSL; the L2TP, IPSec, and PPTP are not supported.
  • Third-party plug-ins and scripts can be used to improve processes such as login and authentication.
  • Since it offers support for a private subnet configuration, clients can actually connect to servers beyond the OpenVPN server.
  • To protect users from DoS attacks, buffer overflow vulnerabilities in TLS/SSL implementations, port flooding, and port scanning, OpenVPN relies on tls-auth for HMAC signature verification.
  • OpenVPN does not run in kernel space; instead, it runs in userspace.
  • It runs on many devices and platforms such as Windows XP, 2000, Vista, 7 & 8, and supports Linux, Android, Maemo, FreeBSD, OpenBSD, NetBSD, and Windows Phone.

Is it Safe to Use?

The answer to this question is, “Yes.” And it’s not just my opinion; if you ask any security expert out there about the safest VPN protocol, their answer will most probably be OpenVPN. 

In 2017, OpenVPN underwent two security audits, which only found minor issues that didn’t endanger user data. The other only found two bugs that, too, were fixed very quickly and easily.

Also, on the official website of OpenVPN, there is a large in-depth list of what users can do to further secure their connections after configuring this VPN protocol on their devices. As mentioned above, OpenVPN is an open-source protocol, making it much more trustworthy since you can check out the code yourself (if you know how) to make sure everything is in order. 

So if you want to enjoy a private, surveillance, and hacker-free online experience, then OpenVPN is what you should opt for.


I think this is the only thing that OpenVPN lacks, and it has something to do with its strong encryption and some other factors. But it does not mean that it totally fails in this area as with enough bandwidth, you’ll be able to get decent connection speeds. You can get faster speeds if you use OpenVPN over user datagram protocol instead of the transmission control protocol.

Advantages and Disadvantages


  • As mentioned above, OpenVPN is one of the safest VPN protocols out there as it makes use of several strong encryption techniques and algorithms. 
  • It can easily work its way around any firewall it encounters.
  • This protocol can use both user datagram protocol and transmission control protocol, and it offers its users more control over their connections.
  • It has support for Perfect Forward Secrecy.


    • There’s a great deal of technical knowledge required to harness the complete advantages of OpenVPN.
    • Despite its support for a large number of platforms, it’d be somewhat difficult to manually set-up this protocol on some platforms.
    • As mentioned above, speed is not its strong suit, and you might face drops in connection speed for some reasons, one of which is its strong encryption.
    • OpenVPN’s other disadvantage is its huge dependence on third-party software and applications.

The Bottom Line 

The advantages that you can get by opting for this open-source VPN protocol are way too many, and the level of encryption provided by this VPN software is also a cut above the rest. If you want to gain from the advantages of using this service, choose a VPN provider that provides access to OpenVPN connections but also offers access to other VPN protocols. There are several services out there that don’t support it.

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