OpenVPN works by building a secure, encrypted tunnel between your device (the VPN client) and a VPN server. Here’s a beginner-friendly overview of the process:

• Authentication: First, OpenVPN checks identities. Your device and the VPN server each prove who they are using credentials (like usernames/passwords or digital certificates)nordvpn.comnordvpn.com. This step ensures you’re connecting to a legitimate VPN server and not an imposter.

• Tunnel Setup: Once both sides are authenticated, OpenVPN establishes an encrypted tunnel between them. It typically uses the SSL/TLS protocol (the same kind of technology that secures websites) to create this tunnelnordvpn.com.

• Encryption: Your internet data is then wrapped inside this tunnel. OpenVPN encrypts (scrambles) the data packets using strong ciphers (by default AES-256)nordvpn.comsecurity.org. This means anyone spying on the connection – like your ISP or a hacker – would only see gibberish. OpenVPN is highly versatile: you can choose different encryption algorithms and key lengths if needednordvpn.comsecurity.org.
  

• Data Transmission: Finally, the encrypted data travels through the tunnel to the VPN servernordvpn.com. The VPN server decrypts it and forwards it to the internet on your behalf. Because the server’s IP address is used, websites and services only see the server’s location – not your real IPnordvpn.com.
  

Put simply, OpenVPN takes your data, seals it in a locked box (the encrypted tunnel), and sends it safely to the VPN server. The server then unlocks the box and sends the data on its way. This keeps your browsing private and secure even on public Wi-Fi or untrusted networks.

There are several VPN protocols besides OpenVPN. Two popular ones are WireGuard and IKEv2/IPsec. Here’s how they compare in simple terms:

• OpenVPN – Speed: Moderate (can be a bit slower than newer protocols)nordvpn.com. Security: Extremely high – supports 256-bit AES encryption and OpenSSL, making it “built like a tank”security.org. Flexibility: Very flexible – works on almost any port (including TCP or UDP), so it can bypass many firewallsgoodaccess.comnordvpn.com. Use case: Great for high security and compatibility. Runs on Windows, Mac, Linux, iOS, Android, routers, etc.security.orgnordvpn.com.
  

• WireGuard – Speed: Very fast – designed to be lightweight and efficientavast.com. Security: Strong – uses modern encryption (ChaCha20)security.org. Its code is smaller and easier to auditavast.com. Newness: It’s newer, so still being tested in the wildavast.com. Use case: Ideal for performance (streaming, gaming) and newer devices. However, it may lack some advanced features and, by default, keeps static IPs which can be a privacy concernavast.comsecurity.org.
  

• IKEv2/IPsec – Speed: Fast and very stable (reconnects quickly, making it excellent for mobile devices)avast.com. Security: Strong (uses AES/IPsec) but it’s not open-source. Some privacy experts note that IKEv2/IPsec was partly developed by security agencies, raising theoretical concernssecurity.org. Use case: Built into many devices (especially Windows and iOS) for easy setupavast.com. Great for mobile users because it handles network changes well (e.g. switching from Wi-Fi to cellular)avast.com.
  
  

Below is a quick comparison table:

Each protocol has trade-offs. For example, OpenVPN can run on any port (even port 443) to get through firewalls, which is harder for IKEv2. WireGuard is faster and simpler, but OpenVPN is more proven and configurablesecurity.orgavast.com. Avast’s analysis notes that “OpenVPN is the stronger option if security is the top priority”, while IKEv2 has the edge in speed and stability on mobileavast.com. In practice, many VPN apps let you switch between these protocols depending on your needs.

Pros and Cons of OpenVPN

Pros:

• High Security: Uses top-grade encryption (AES-256) and open-source OpenSSL. It’s often described as “built like a tank” for encryption security.org.

• Open-Source: Anyone can inspect or improve the code nordvpn.com, so vulnerabilities are caught quickly.

• Flexible & Compatible: Works on almost any device or platform (Windows, Mac, Linux, iOS, Android, routers, etc.)security.org nordvpn.com. Can use either TCP or UDP on any port nordvpn.com.

• Bypasses Blocks: Can usually tunnel around firewalls or ISP blocks by running on common ports goodaccess.com.
  
  

Cons:

• Speed/Overhead: It is slower than some newer protocols like WireGuardnordvpn.com. The encryption and extra headers add overhead.

• Setup: May require manual setup or a third-party client (though most VPN apps do this for you)nordvpn.com. It’s generally more complex than built-in options.

• Resource Use: Can be more CPU-intensive on older hardware or routersnordvpn.com.

• Latency: If using the TCP mode for reliability, it can introduce more latency. (UDP mode is faster but less reliable.)
  
  

Overall, OpenVPN’s strength is its rock-solid security and adaptability. Its weakness is mainly that it can be slower and a bit more complex than some newer protocolsnordvpn.comsecurity.org.

Many popular VPN services support OpenVPN. Here are a few well-known examples:

• NordVPN: A leading VPN provider that offers OpenVPN (on both UDP and TCP) as well as its own NordLynx protocol. NordVPN uses strong AES-256-GCM encryptioncyberinsider.com. The NordVPN apps let you easily select OpenVPN if you prefer maximum compatibility cyberinsider.com nordvpn.com.
  

• ExpressVPN: Another top VPN service that fully supports OpenVPN. In ExpressVPN’s apps, OpenVPN is labeled as “UDP” or “TCP” (the two transport protocols) and can be chosen for any device xpressvpn.com. ExpressVPN notes that OpenVPN is “open source” and “extremely secure”, backing the same AES-256 encryption expressvpn.com.
  

• ProtonVPN: Known for strong privacy features, ProtonVPN’s apps support OpenVPN (as well as WireGuard and IKEv2) cyberinsider.com. ProtonVPN also uses AES-256-CBC and HMAC SHA-512 for security cyberinsider.com. You can select OpenVPN in the ProtonVPN settings on desktops and mobile.
  

  (Others:) Many other VPN providers like Surfshark, CyberGhost, TunnelBear, etc., also include OpenVPN. If security and flexibility are your priority, choosing a VPN that offers OpenVPN is often a safe bet.

OpenVPN remains a popular and trusted VPN protocol thanks to its strong security and wide support. It uses AES-256 encryption and open-source code, making it extremely secure and transparent security.org avast.com. While it may not be the fastest option for every use case, it excels at keeping data private and bypassing network restrictions. In short, if you value maximum security and flexibility, OpenVPN is an excellent choice – and is used by almost all major VPN services security.org  nordvpn.com.

1. What is OpenVPN?
OpenVPN is an open-source VPN protocol that creates a secure, encrypted tunnel between your device and a VPN server nordvpn.com. It hides your IP address and protects data by encrypting internet traffic (often with AES-256) as it travels through this tunnel.

2. How secure is OpenVPN?
OpenVPN is considered very secure. It supports AES-256 encryption (256-bit AES is the highest standard) and uses SSL/TLS for authentication security.org. Because its code is open-source, experts can audit it, helping ensure no backdoors are hiding. In fact, OpenVPN is often called one of the most secure VPN protocols available security.org avast.com.

3. How does OpenVPN differ from WireGuard or IKEv2?
OpenVPN is older and very mature. It runs on many ports and devices, and it’s extremely securenordvpn.com security.org. WireGuard is newer and much faster, but with a smaller codebase and still gaining trust avast.comsecurity.org. IKEv2 is fast and great for mobile (quick reconnect), but it’s not open-source and has different security considerations security.orgavast.com. In short, WireGuard is speed-oriented, IKEv2 is stable on phones, while OpenVPN is focused on maximum compatibility and security.

4. Which devices or apps support OpenVPN?
Almost all major devices support OpenVPN. There are official OpenVPN apps/clients for Windows, macOS, Linux, iOS, Android and many routers security.org. Most commercial VPN services include OpenVPN in their apps. If your VPN provider offers an app or a config file, you can usually connect with OpenVPN on any of the above platforms.

5. Is OpenVPN free to use?
Yes. The OpenVPN protocol and reference software are free and open-source nordvpn.com. You can download the OpenVPN client for free and use it to connect to any VPN server (your own or one provided by a VPN service). Many VPN apps and operating systems support OpenVPN without extra cost. Just keep in mind that while the protocol is free, a VPN service that runs OpenVPN (and provides server access) typically requires a subscription.