From the outside, a VPN is just an app with one "Connect" button. But under the hood there's a rather elegant chain of events, and understanding that chain helps you troubleshoot quickly when things go wrong: speed drops, sites don't open, the connection cuts out.
Let's go step by step through what actually happens to your traffic when you turn on a VPN.
Without a VPN: what a normal connection looks like
When you open a website the usual way, the request goes straight to your ISP. The ISP sees who's connecting, where, when, and for how long. Then it forwards the request through a chain of servers to the target site. The site also sees your real IP and can determine your rough location.
So: the ISP knows what sites you visit. Sites know who you are and where you're from. That's how the internet normally works — but it's also a privacy problem. On top of that, your traffic passes through dozens of intermediate routers between you and the site — and at any of them, if the traffic isn't encrypted on its own (HTTP rather than HTTPS), it can be read.
With a VPN: what changes
Once the VPN is on, a middleman appears between your device and the internet — the VPN server. Everything happens in four steps.
Step 1. App launch and authentication
The VPN app connects to the server and verifies that you have a valid subscription. Encryption keys are exchanged here too, in a fraction of a second. This uses asymmetric cryptography: the keys you and the server will use to encrypt the actual traffic are negotiated over a tamper-proof protocol (most commonly based on Diffie-Hellman or X25519).
Step 2. Tunnel setup
An encrypted channel is established between your device and the VPN server — this is the "tunnel". Anything entering it is automatically encrypted on your side and decrypted on the server. From the operating system's point of view it looks like a virtual network interface — hence the name "virtual private network".
Step 3. Traffic encryption
When you open a website, your request is first encrypted — turned into meaningless bytes for any observer. It travels in that form to the VPN server. Even if someone technically intercepts a packet along the way — ISP, public Wi-Fi, a national filter — they see only an encrypted block and the fact of a connection to a VPN server.
Step 4. Exit to the internet with a new IP
The VPN server decrypts the request and forwards it to the target site — but under its own name. The site sees the server's IP (for example, German), not your real one. The response comes back the same way in reverse: the site replies to the server, the server encrypts the response and sends it back into the tunnel, the app on your device decrypts it and hands it to the browser.
What protocols are and why there are several
A protocol is the set of rules for establishing the tunnel and encrypting traffic. Different protocols are optimized for different goals:
- WireGuard. Modern, fast, lightweight. The best default — speed and stability. Just ~4,000 lines of code (vs. 100,000+ for OpenVPN), which makes security audits much easier.
- OpenVPN. Battle-tested, very reliable, but a bit slower than WireGuard. Handles restrictive networks well — it can disguise its traffic as regular HTTPS, so it works even on networks where other VPN protocols get blocked.
- IKEv2/IPsec. Excellent on mobile — quickly rebuilds the connection when the phone switches between Wi-Fi and 4G.
You usually don't need to pick the protocol yourself — the VolnaLink app selects the best one automatically based on your device and network.
Where a VPN server physically lives
A VPN server is an ordinary server in a data center in some country. VolnaLink VPN runs 100+ servers across different locations worldwide. The location matters: the closer the server is to you geographically, the faster the connection. The intuition is simple: light in fiber is no faster than light in vacuum, so distance is a physical latency floor.
Often location choice is dictated not by proximity but by purpose. Want access to US Netflix — a server in the US, even if it's 8,000 km away. Want to reach a "home" site from abroad — a server in your country. For day-to-day privacy — just pick the nearest fast one.
What happens if the connection drops
A decent VPN has a kill switch: if the tunnel suddenly breaks, the entire internet on the device is temporarily blocked. This protects you from a situation where you think you're using a VPN but you're actually not. Without a kill switch, the moment the tunnel drops your real IP leaks to any site with an open session — a small but real risk, especially if you use a VPN specifically for privacy.
In VolnaLink the kill switch is on by default — the only reason to disable it is in rare cases, for example when configuring allowed local resources.
Why speed can drop
Three main reasons:
- Physical distance to the server. A server in Singapore from Europe will always be slower than a nearby one in Germany.
- Server load. If a thousand users share one server, speed gets divided.
- Encryption overhead. Processing takes time, even if minimal. On modern CPUs the encryption overhead is a few percent.
If your VPN is noticeably slow — we covered what to do about it in why your VPN is slow.
What DNS leaks are and why they matter
When you type "google.com" in the browser, your device asks a DNS server: "what IP does this name have?". Without a VPN the DNS request goes to your ISP's server — so they see what sites you visit even if the traffic itself is encrypted (HTTPS).
If a VPN is poorly configured, DNS requests go outside the tunnel — straight to the ISP. Traffic is encrypted, but the site names leak. A proper VPN routes DNS through the tunnel too, and each server runs its own resolvers. VolnaLink does this by default, no action required. You can check whether your current VPN leaks DNS on dnsleaktest.com.
The bottom line
A VPN is a layer between your device and the internet that does two things: encrypts traffic and swaps your visible IP. Under the hood — a tunnel, cryptography, protocols, server infrastructure. For the user it all boils down to one button, but now you know what's behind it.
Ready to try it? VolnaLink VPN works on every popular device with automatic protocol selection, protected DNS, and the kill switch on by default.