Cautions When Using a VPN

A VPN is a useful mechanism for changing route visibility.

When you use a VPN, the destination website sees the VPN server's IP address instead of your home or workplace IP address. VPNs are also used to protect communication on public Wi-Fi, make it harder to show your home IP directly to destinations, and connect to internal company networks.

However, a VPN is not automatically enough for anonymity.

When you use a VPN, the trusted party changes. Even if the IP visible to the destination changes, you are placing trust in the VPN provider.

What changes with a VPN

When you use a VPN, a communication path is created from your device to the VPN server. Your external communication then goes through that VPN server.

From the destination website's point of view, the source of access is the VPN server.

A VPN changes how the source IP appears. It does not erase every piece of information related to you.

The easiest change to understand with a VPN is the IP address visible to the destination. It appears as the VPN server's IP instead of the IP of your home line or workplace line. For that reason, it is useful when you do not want to show your home IP directly to the destination.

However, a VPN does not reset what is inside the browser. Cookies, login state, browser fingerprint, post content, file metadata, writing style, and posting time remain as separate issues. Even if you use a VPN, logging in to a real-name account links that activity to the account.

You are trusting the VPN provider

When you use a VPN, the VPN provider becomes an important trusted party.

Instead of making the destination harder for the ISP to see directly, the VPN provider becomes the relay point for communication.

For that reason, check the following points.

• Logging policy
• Operator
• Jurisdiction
• Whether audits exist
• Whether the app is open source
• How DNS is handled
• Payment methods

If you are looking for candidates, first check services with substantial official information.

Proton VPN is a VPN from Proton, which has long operated privacy-focused services. You can confirm supported devices, servers, privacy policy, no-logs policy audits, open-source apps, and transparency reports from official information. The transparency report lets you check the policy for responding to legal requests and past response status.

Proton VPN official site URL : https://protonvpn.com/

Proton VPN transparency report URL : https://protonvpn.com/blog/transparency-report

Mullvad VPN is also a service that users who care about anonymity can easily compare. It uses a design based on random-number accounts without requiring an email address or password. Its official logging policy explains that it does not store traffic contents, DNS requests, connection timestamps, IP addresses, or bandwidth as activity logs. It also officially disclosed that when it received a search warrant from Swedish authorities in 2023, nothing was seized because customer data did not exist.

Mullvad VPN official site URL : https://mullvad.net/

Mullvad VPN logging policy URL : https://mullvad.net/en/help/no-logging-data-policy

When you use a VPN, some information that was visible to the ISP moves to the VPN provider's side. This means that "the trusted party moves." Instead of making the destination harder for the ISP to see directly, the VPN provider becomes the relay point for the connection. That is why a VPN should not be chosen only by service-name recognition.

Does it explain that it does not store logs? Are there external audits? Does it explain the app and protocols? How does it handle DNS? Which country or legal jurisdiction is it operated under? How does it handle payment information and account information? Check these points.

Cookies and login state do not disappear

Even if you use a VPN, cookies and login state do not disappear.

If you access the same site with the same browser, cookies are sent. If you log in to a real-name account, the activity links to the account.

Even if only the IP address changes, correlation remains if other identifiers remain.

When using a VPN, you also need to think about an anonymous-use browser, cookie management, and account separation.

For example, suppose you turn on a VPN and open a social media site in your usual browser. The IP visible to the destination becomes the VPN server. However, the social media site receives the logged-in account, cookies, and browser information. As a result, even though the IP has changed, you are treated as the same user.

A VPN is not a substitute for account separation or browser separation. If anonymity is needed, you need to separate real-name logins, cookies, browsers, and post content before deciding whether to use a VPN.

DNS leaks and kill switches

One point to watch when using a VPN is DNS leaks.

If only DNS queries go out through the normal ISP side, which domains you tried to view can be visible through a separate route.

Also, if the connection returns to the ordinary connection when the VPN connection drops, communication may occur with your original IP address.

To prevent this, check the VPN app's DNS settings and kill switch feature. A kill switch is a feature that prevents communication over the ordinary connection when the VPN drops.

If a DNS leak occurs, the body of the web page may go through the VPN while the domains you tried to view are visible through a separate route. If your purpose for using a VPN is to hide destinations, DNS handling matters.

Check the kill switch as well. If the VPN drops for a moment and returns to the ordinary connection, communication may occur with your home or workplace IP. If this happens during posting, login, or file sending in particular, an unintended IP may remain. Look at the VPN app settings and understand what happens when it disconnects.

Be careful with free VPNs

Free VPNs require caution.

A VPN provider becomes a relay point for communication. Operating it also costs money.

If it is provided for free, you need to look carefully at the operating policy, advertising, data use, logs, and app behavior.

Instead of thinking "it is free, so I will try it," think about whether you can trust that party as someone who will relay your communication.

This does not mean that all free VPNs are bad. However, because a VPN becomes a relay point for communication, how it is operated matters. Services with unclear advertising revenue, data use, log storage, app permissions, or operators become difficult to treat as a foundation for anonymity.

If your purpose for using a VPN relates to privacy or anonymity, look at the trust model, not only the price. To whom are you entrusting communication? What can that party record? If a problem occurs, which legal jurisdiction affects it? It is important to keep these questions in mind.

What to check before using a VPN

Before using a VPN, decide the purpose. Do you want to protect communication on public Wi-Fi? Do you not want to show your home IP to the destination? Do you not want to access directly from a workplace or school network? Do you want to avoid regional restrictions? The points you need to check change depending on the purpose.

A VPN is a useful tool, but it is not all-purpose. Use it after checking the information that remains outside the VPN.

Summary

A VPN is a mechanism that changes the IP address visible to the destination to the VPN server.

It is useful for protecting communication on public Wi-Fi and making it harder to show your home IP to destinations.

However, a VPN is not automatically enough for anonymity. You need to trust the VPN provider, and you need to check cookies, login state, browser information, post content, DNS leaks, and communication when the VPN disconnects separately.

When using a VPN, it is important to organize who can see what instead of judging only by the service name.

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