A determined website operator has lots of ways to tell if you’re using a VPN, and most are quite easily implemented. Additionally, in countries with severe censorship, local ISPs often use an advanced VPN-detection technique called deep packet inspection.
If you struggle to access some websites even with a VPN connected, keep reading. I’ll explain why organizations check for VPN usage and reveal the most common methods they use.
How to know if someone is using a VPN
Website owners can gather information about their site’s visitors using free analytics tools, cookies, and browser fingerprinting. This is often done to measure marketing effectiveness, better understand a site’s user base, or to comply with local laws. However, examining this data may reveal location mismatches or strange usage patterns that could indicate VPN usage.
Here are some of the easiest ways to tell if a VPN is being used:
- Block known VPN IP addresses. This is arguably the most effective way to identify VPN users quickly (which is why streaming services like Netflix use it). The downside is that no filter list could possibly contain the address of every commercial VPN server.
- Block ports known for VPN traffic. By default, OpenVPN traffic goes through port 1194, and WireGuard uses port 51820. Rejecting traffic from these ports will block VPN users, though they can simply use a different port.
- Determine the user’s location. If the user grants GPS or location permissions, you can easily determine their location. Even without these, it’s possible to get their approximate location using an IP address lookup service or by checking their device’s time zone. If any of this information is contradictory, they may be using a VPN.
- Use tracking cookies. Saving cookies with a unique identifier lets you identify specific users even if their location, account, or IP address changes. If the same person visits your site from all over the world, they’re likely using a VPN. However, this method can be sidestepped by clearing cookies after each visit.
VPN detectors: Why are they used and how effective are they?
VPNs are fantastic security tools, but, as counterintuitive as it may seem, so are VPN detectors. Among other things, they help banks identify suspicious login attempts and websites detect users trying to circumvent bans. While not every VPN user is a threat (and it’s impossible to identify them all), VPN detection remains hugely important. Here’s everything you need to know about detecting VPN usage.
Why do some websites block VPNs?
Websites block VPN users for all kinds of legal, commercial, and political reasons, including:
- Copyright restrictions. Companies may have rights to sell or stream their content only in specific countries. That’s why platforms like Hulu and BBC iPlayer aren’t available globally. Breaching this (for instance, by failing to implement robust location-verification measures) would likely result in fines and termination of licensing agreements.
- Compliance with gambling laws. Gambling websites are highly regulated and legally required to verify their customers are within specific countries. This is primarily done via Know Your Customer checks, but blocking VPNs is another great line of defense.
- Protecting their business. Services like Spotify have different pricing for different countries. Blocking VPN users ensures people can’t just spoof their location and sign up wherever is cheapest. It also helps filter out people looking to hide their identities for reasons like trolling, spamming, or committing e-commerce fraud.
An example showing why services with regional pricing frequently try to block VPN users - Ensuring accurate site analytics. Making informed business decisions is hard when you can’t tell where your site visitors are or how often they visit. Blocking VPNs doesn’t guarantee accurate info, but it does remove one popular method of shielding your identity.
- Government censorship. Countries like China and North Korea block VPNs to prevent citizens from bypassing their extreme digital censorship. Websites in free countries may block VPN users just to avoid expensive legal battles with foreign governments.
Can my ISP tell if I’m using a VPN?
Yes – your Internet Service Provider knows when you’re connected to a VPN. However, they can see the IP address of your chosen server, bandwidth usage, how long you’ve been connected, and which port data is being sent over.
You might be asking yourself what the point of using a VPN is, considering all of this information remains visible. The crucial thing is that your ISP can’t see what really matters: which sites you visit or what you do there. They also won’t know which files you download or the contents of any messages you send.
| When using a VPN, your ISP can see | But not |
|---|---|
| Your real IP address | Which sites you visit |
| Your VPN’s servers IP address | Any files you download |
| Connection timestamps | Info entered in website fields |
| Bandwidth consumption | Search and browsing history |
| Ports used | What activity you’re doing (browisng, streaming, torrenting, etc.) |
Your ISP may also use deep packet inspection (DPI), which allows them to identify VPN users with greater accuracy. DPI works by analyzing the contents of your data packets, not just the headers. This means accounting for ports used as well as packet size and timing, plus searching for recognizable VPN traffic patterns. However, DPI is only really an issue if you’re somewhere VPNs are illegal. Even then, using DPI won’t help anyone decrypt your traffic.
Is it legal to use a VPN?
In most countries, using a VPN is completely legal. There are some exceptions, such as China (where only state-approved providers are legal) or Iraq (where all VPNs are illegal). Additionally, in places where VPN usage is legal, using one in furtherance of a crime may be an aggravating factor. So long as you don’t use a VPN for anything illegal, most people should be fine.
When won’t a VPN hide your identity?
All the privacy tools in the world won’t help if you allow yourself to be tracked. Whenever you log in to a personal account, you’re identifying yourself, since nobody else should know the correct credentials. Similarly, VPNs won’t protect your anonymity if you post personally identifiable info online or if their DNS and IPv6 leak protection features are disabled.
Consistency is key: there’s no point in using a VPN if you’re going to accept cookies on every site you visit or sign in to Google or Facebook. I’d suggest ditching data-hungry services like Google Chrome or Microsoft Edge since free, privacy-conscious alternatives like Brave and Firefox exist.
Final thoughts
Whether you’re looking to hide or detect VPN usage, you have plenty of tools at your disposal. That said, as surveillance becomes more common and online freedoms continue to decline, the need for reliable workarounds increases too. It’s in a VPN provider’s best interests to remain undetectable, which is why obfuscated connection protocols are becoming more common. Love them or loathe them, VPNs are here to stay.
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