What is a DNS leak?
A DNS leak is a situation in which third parties can obtain the IP address of the nearest DNS (Domain Name System) server through which your browser had sent a request, or some plug-in in the browser, despite the fact that you are using a VPN service or a proxy anonymizer.
Each time you enter the address of a website in your browser, for example instagram.com, your browser connects to a certain DNS server and converts the domain name to the IP address of the server you want to access.
In the event that you use a VPN connection, proxy anonymization or similar technologies to securely visit the Internet, the first request from the browser goes to the DNS server of your anonymization service.
However, if the browser does not receive a response from this DNS server for some time during the timeout, the request is automatically sent to the DNS server that your Internet provider specified.
As a rule, this server belongs to the same provider and is geographically closer to you than the DNS server of the anonymization service.
To prevent this situation, it is sufficient to force the preferred DNS server in the settings of your network connection, which can be any public DNS server.
Examples of such DNS servers are: