How does a VPN work, and do I need one?

How does a VPN work?

A VPN works to protect your privacy by (A) encrypting your internet traffic, making it look like gibberish to anyone trying to intercept it, and (B) forwarding all your internet traffic under its own server’s IP address, masking yours so websites and apps don’t learn as much about you via your device.

Using a VPN on your phone or computer generally follows these steps:

1. You open your VPN app and select a server to connect to (or just press On to have your VPN app select the fastest one). Most VPN providers host servers all over the world.
2. As you visit websites and use apps, your VPN encrypts every data request leaving your device. Encryption converts readable information about your web interactions—anything from which buttons you click to the password you enter or the credit card you pay with—into coded data. Anyone who intercepts properly encrypted traffic should not be able to understand it without the correct encryption key.
3. The VPN server receives your encrypted data requests and forwards them to the server of the website, app, or service you’re using. When this happens, websites/apps typically see the VPN server’s IP address instead of the IP address assigned to your home internet connection.
4. The website, app, or service serves the data you requested back to your VPN.
5. The VPN encrypts the reply and sends it back to your device.

VPN benefits: what do they protect you from?

Understanding how a VPN works tells us a bit about what it can do. The encryption makes a VPN ideal for protection from hackers trying to intercept sensitive information, while the IP masking offers some privacy from websites and apps that may be tracking you.

These are four of the most common situations when a VPN can reduce your security risks or give you a bit of privacy back:

• Using a public Wi-Fi network. When it comes to Wi-Fi, “public” is actually a technical category—and essentially what it means is “unsecured.” On a Wi-Fi network set to public, every data packet on every device is readable to those who know where to look for it. Encryption makes your traffic a completely unappealing target to a casual thief and a challenging target to a more sophisticated one.
• Frequent changes in your network connection, e.g., while traveling. As you move between hotels, airports, or even just your favorite local cafés throughout the week, using a VPN can give your internet traffic an added layer of protection.
• Exposure by cybersecurity attacks. Cyberthieves are always at work—globally—and your devices can be affected even when you’re on more secure networks. A VPN can provide an additional layer of protection when accessing sensitive information.
• IP location-based tracking. Because websites generally see the VPN server’s IP address instead of yours, a VPN can help hide your approximate location and make it more difficult for web publishers to associate your activity with your regular IP address.

Limitations of VPN protection

Analyzing how a VPN works also indicates what it can’t do. A VPN protects data in transit between your device and the servers it communicates with—nothing more, nothing less. Here are some key limitations to keep in mind.

• Cannot screen, verify, or automatically block websites, links, or email attachments. For that, you’ll need to lean on other security tools, like antivirus software. And your own street smarts.
• Cannot eliminate online tracking. IP detection is just one form of tracking. A VPN can’t stop data collection from other technologies like cookies and browser fingerprinting, and it can’t override the data collection you agree to when you use or log into your account on certain sites.
• Cannot guarantee access to every site/app you use. Some services require your exact location to work at all. Some apps block IP addresses known to belong to VPN providers. Some web publishers preemptively block mass traffic coming from a single IP address because it’s harder to prevent fraud when you can’t identify individual devices or households, or when you get conflicting information about a user’s location vs. their account details.
• Cannot make you invisible to your VPN provider. Your VPN provider may still be able to see some information about your connection, which is why the provider’s privacy practices matter.

As you can see, you still need to practice good security habits (caution around unfamiliar links, turning on automatic software updates, multifactor authentication, etc.) to protect yourself online. Additional products, like antivirus protection and password managers, can also address risks that a VPN does not.

A note on VPNs for streaming

In theory, using a VPN for streaming provides the same encryption and IP-based privacy protections you’d get during any other online activity. But because streaming libraries are often licensed for particular regions, these platforms frequently block users whose IP addresses suggest VPN activity.

So even if you’ve chosen a server within your geographical region, you may not be able to stream your shows. And if you’ve purposefully chosen a VPN for streaming out-of-area content on the sly, be aware that that’s usually a violation of the terms of service.

Do I need a VPN?

Answering Do I need a VPN? is not always a simple yes or no, but you can get started with a simple checklist about your internet habits. The more of these situations apply to you, the more useful a VPN may be.

• I regularly rely on public or shared Wi-Fi or unfamiliar networks.
• I work remotely or handle sensitive information online.
• I want protection that travels with my devices.
• I want to limit the exposure of my home IP address.
• I prefer added privacy for everyday browsing.

If you checked only a few boxes, or you checked many but they don’t apply very often, a VPN could still be worth considering on a temporary or limited basis. Most VPN providers offer monthly options, so you can sign up and cancel at will. 

And if turning your VPN off and on sounds like a pain, you could keep it off at home where your private Wi-Fi is already encrypted, and just use it for extra protection on unfamiliar networks.

Times when you may need, or want to disconnect your VPN:

• A website, or app will not work while it’s on.
• You need the lowest possible latency for an online activity.
• A banking, telehealth, government, or shopping site flags the VPN connection as unusual.
• You need a service to detect your actual location.

How to choose a VPN

Once you understand how a VPN works and whether you need or want one, you can get shopping.

Don’t just rely on a general promise of anonymity. Look for a VPN provider that clearly explains its privacy practices and offers tools suited to your habits. Compare these factors across multiple providers:

• Encryption protocols
• Privacy policy
• Number and types of supported devices
• Server availability 
• Connection performance, especially during favorite activities
• Accessible technical support
• Security tools that complement the VPN

Performance deserves particular attention if you want a VPN for streaming, video calls, gaming, or other bandwidth-heavy activities. No VPN can guarantee identical speeds under all conditions.

You should also decide whether you want a standalone VPN, or a broader security package. A package that includes malware protection and a password manager can address risks that encryption and IP masking cannot.

Frequently asked questions