What a VPN changes, and what it doesn’t
VPN adverts promise to make you anonymous, invisible and safe. In this lesson you’ll skip the promises and measure it: write down what websites and your provider see, switch a VPN on, and look again. Some things change completely. Some don’t move at all.
In this lesson
- Record your “before” picture with tools from Lessons 1 and 2
- Switch on a VPN and measure exactly what changes
- Understand who can see your traffic once the VPN is on
You’ll need: a computer or phone and a VPN app. No VPN? You can still do part 1 and read along; on a phone, switching from Wi-Fi to mobile data shows you a similar change of network for free.
What a VPN actually does
A VPN app makes an encrypted connection, a tunnel, from your device to a server run by the VPN company. All your traffic goes through the tunnel and comes out of that server onto the internet. That has two effects:
- Websites see the VPN server, not you. Its IP address, its provider and its location replace yours.
- Your provider sees only the tunnel. It can tell you’re connected to a VPN, and how much data moves, but not which sites you visit. The VPN company now sits where your provider used to.
That last point is the one adverts leave out. A VPN doesn’t remove anyone’s view of your traffic; it moves it to the VPN company. Choosing a VPN is choosing who you trust with it.
Try it yourself · part 1
Record your “before” picture
With the VPN off, write down each of these on paper or in a note. You’ll check the same list again with the VPN on.
| Write down | Where to find it |
|---|---|
| Public IP address (first few digits) | IP checker |
| Provider | IP checker |
| Connection label | IP checker |
| Location | IP checker |
| Who answers your DNS | whoami.akamai.net lookup, then ASN lookup (Lesson 2) |
| Timezone line | What We Know |
| Canvas fingerprint (first few characters) | What We Know |
| Are you still logged in to your email? | Your email tab |
Try it yourself · part 2
Switch the VPN on and measure again
- Connect your VPN. If it lets you choose, pick a server in another country; it makes the changes easier to see.
- Reload the IP checker. The address, provider and location are now the VPN server’s. The label should say VPN or datacentre network: that’s how websites spot most VPNs, by recognising data-centre addresses.
- Run the
whoami.akamai.netlookup again and check it in the ASN lookup. With most VPNs, the DNS server that answers is now the VPN company’s, not your provider’s. (If it’s still your provider’s, your VPN has a DNS leak. Lesson 6 is all about that.) - Reload What We Know. Look at the Timezone line: your device’s clock still says your real timezone, while the IP address now points somewhere else. The page flags the mismatch, because it’s one of the ways sites guess that a visitor is using a VPN.
- Look at the canvas fingerprint. It hasn’t changed: it comes from your device, not your connection.
- Open your email. You’re still logged in. The site knows exactly who you are, VPN or not.
- Optional: run the Privacy Exposure Score again and compare it with your score from Lesson 1.
The results, side by side
| Changed by the VPN | Not changed by the VPN |
|---|---|
| The IP address, provider and location websites see | Your accounts: logging in identifies you as before |
| Your provider’s view: one tunnel instead of a list of sites | Cookies already in your browser |
| Who answers your DNS lookups (usually) | Your browser fingerprint and timezone |
| Who can see the sites you visit: now the VPN company | What you type, post and share |
When a VPN is worth it
- Public Wi-Fi. On a café, hotel or airport network, a VPN stops the network operator and other users seeing which sites you use. (On a fake login page it can’t save you; that’s a scam to recognise, not a connection to encrypt.)
- Hiding your browsing from your provider. If you’d rather your provider didn’t hold a list of your sites, a VPN moves it to a company you’ve chosen.
- Not handing your home IP to every site. Useful for games, forums and anywhere people might try something with your address.
- Getting around network blocks. On restricted networks, and where it’s legal, which in most countries it is. See Are VPNs Legal?.
It’s not worth much for staying anonymous from sites you log in to, for stopping trackers (Lesson 3 does that better) or for protecting you from scams. And because the VPN company sees everything your provider used to, a free VPN that makes its money from your data can leave you worse off than none. Are Free VPNs Safe? explains how to tell.
Key takeaways
- A VPN replaces your IP address, provider and location with the VPN server’s.
- Your provider sees only an encrypted tunnel; the VPN company sees what your provider used to.
- Websites can often tell you use a VPN, from data-centre addresses and timezone mismatches.
- Logins, cookies, your fingerprint and what you type are unchanged by a VPN.
- Choosing a VPN means choosing who you trust with your traffic.
Check yourself
Three questions. Pick one answer each and you’ll see why.
1. You switch on a VPN. Who can now see which websites you visit, in place of your internet provider?
2. With the VPN on, you open your email and you’re still logged in. What does the email service know?
3. How can a website often tell you’re using a VPN?
Want the background? What Is a VPN? explains how the tunnel works, and Best VPN for Privacy: What to Actually Look For is a checklist for choosing one.
This lesson is part of the free course Privacy and VPNs, licensed under CC BY-NC-SA 4.0: you may share and adapt it for non-commercial use, with credit to ExamineIP and a link to the original.