Implementing a VPN Server in Rust

Luis Soares

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Dev Genius

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14 min read

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Oct 29

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Interested in understanding the inner workings of a VPN? Thinking about setting up your own VPN server? Today, we’re taking a straightforward look at how to set up a basic VPN server using Rust.

In this article, we’ll break down the core concepts and guide you through the process with some clear-cut Rust code. By the end, you’ll have a foundational understanding and a basic VPN server to show for it.

Let’s get started!

How a VPN Works

A VPN is essentially a private tunnel between your computer (or another device) and a remote server, usually operated by a VPN service. Here’s how it all breaks down:

1. Initiation: When you launch a VPN client on your device, it reaches out to a VPN server to establish a secure connection.
2. Authentication: The client and server go through a handshake process. They exchange credentials, ensure they’re talking to the right entities, and set up encryption protocols for the session.
3. Tunneling: Once authenticated, a secure tunnel forms between the client and server. This tunnel ensures that data passing through remains confidential and intact.
4. Data Transfer:

• Encryption: Before data leaves your device, the VPN client encrypts it. This turns readable data into scrambled code.
• Transit: The encrypted data travels through the internet, passing through various routers and servers. But to any prying eyes, the data looks like gibberish.
• Decryption: Once the data reaches the VPN server, it’s decrypted, turning it back into a readable format.

5. Exiting to the Internet: The VPN server then sends the data out to the internet to reach its destination (like a website). Importantly, to the outside world (like the website or your ISP), it appears as though the data is coming from the VPN server, not your device. This masks your real IP address.

6. Receiving Data: When data is sent back from the internet, the process reverses. The VPN server receives the data, encrypts it, sends it through the tunnel to your device, where it’s then decrypted for you to see.