Open source VPNs are quite rare, but they do exist. Their transparency makes them a sworn ally for many users, who are quick to recommend them to anyone seeking a free open-source VPN.

Here are some of the best open-source VPNs out there, plus one honorable mention!

1. OpenVPN

What better way to start the list than with a VPN with "open" in its name? OpenVPN isn't as easy to set up as other VPNs, but it is one of the most famous open source VPNs available.

The main draw to OpenVPN is its compatibility with other operating systems. Because OpenVPN can work on the cloud, it puts less responsibility on the client's side. You can connect to it from Windows, iOS, Linux, mobile, whatever you like---as long as you can access the cloud from it.

Download: OpenVPN

Its adaptability and ease-of-use make it one of the best open-source VPNs for Windows, and one of the most highly recommended by users. If you want to know about how the OpenVPN protocol stacks up to the competition, check out our overview of major VPN protocols.

2. SoftEther VPN

SoftEther VPN is also not very intuitive to install and run, but it makes for a great OpenVPN alternative. It's ideal for setting up an open-source VPN server. You can download the tool to set a server up, then use the client software to connect to it.

This makes SoftEther one of the best open-source VPNs for setting everything up yourself---just as you like it!

Download: SoftEther VPN

3. OpenConnect

OpenConnect was developed to accommodate Cisco's own VPN service, AnyConnect. These days, OpenConnect has ascended past its roots and has no affiliation with Cisco.

OpenConnect has a fantastic range of features. For starters, it supports a good number of authentication options, including SSL certificates and OATH. It can connect via an HTTP proxy, a SOCKS5 proxy, and both IPv4 and IPv6.

OpenConnect does require you to set up your own VPN server for it to connect to. Thankfully, OpenConnect offers its own VPN server software, so you can build a VPN from the comfort of your own home.

Download: OpenConnect

4. OpenSwan

OpenSwan is one of the best open-source VPNs for Linux, and has been around since 2005! While it takes a bit of effort to get working, there is an in-depth wiki and a supportive community that can help walk you through configuration.

If you end up enjoying OpenSwan but you have some ideas on improving it, you can! The source for OpenSwan is all visible on GitHub and can be forked for you to work on. Trusting an open-source VPN is one thing; trusting a VPN you can build yourself is another!

Download OpenSwan

5. strongSwan

Another entry based on swans, strongSwan covers an impressive number of operating systems. It can run on Windows, iOS, Linux, and Android. You can grab its official Android app on the Play Store, which makes getting your phone on a proxy server easy.

strongSwan has a good repertoire of features. For example, its Dead Peer Detection monitors when a tunnel goes dead and closes it off. It can also manage firewall rules for IPSec, so you don't have to.

Download: strongSwan

Honorable Mention: Mullvad VPN

If you checked out the above options and glazed over at the sight of the complexity, you're not alone. Not everyone can set up a VPN all by themselves and have it run perfectly fine.

If you read this article hoping for a simple install-and-run VPN service, there's a slight problem. Typically, VPNs require payment in order to maintain decent servers, but this goes against the nature of open source software.

The idea behind showing the source code is that people can download it and run it themselves; why would anyone pay for something they can get for free?

As such, if you want an open-source VPN but you want the ease of a mainstream solution, Mullvad VPN is a good pick. It's not wholly open source, but a lot of it can be viewed on the software's GitHub page. Using Mullvad is as simple as paying for a month, downloading the software, and running it.

If you're interested in the sound of Mullvad, be sure to read our review of Mullvad VPN, where we gave it a very respectable verdict.

Why We Need Libre Software

Libre software (the more technical term for open-source software) may seem like a novelty, but people depend on it every day. The power of open source goes deeper than criticizing the developer's coding practice; it creates a bond of trust.

Let's say you want to send an expensive, fragile package through the mail. Two courier companies step up and offer you their services. When you ask about tracking options, one courier says they use GPS and tracking labels so you always know where the package is. The other refuses to track your package and says "just trust us." Which do you trust the package with?

Software that doesn't reveal its code is known as a "black box." It's as if you had a physical black box in front of you. You put things into one side of the box, and it spits out the result on the other side. You don't know how it does it, but you still get the benefit of the results.

Open-source software is transparent. You know exactly how your data is handled and where it goes. You can see if the software sticks its nose where it doesn't belong. If the developer allows it, you could even branch the code off and add to it yourself!

This is why open-source software is important. By giving users the power to see how their data is used, it removes any fear of misuse and creates an unrivaled level of trust.

The Power of Open-Source Software

If you don't trust a VPN company to preserve your privacy, why not set one up yourself? With free open-source VPN software, you know exactly how your data is being handled. It's tricky to set up, but once it's running, you have complete control over your privacy.

For those of you looking for VPNs just for the Linux operating system, we've rounded up some of the best VPN clients for Linux.