What Is a DNS Leak and How Do I Check for One?
DNS turns domain names into network addresses. A DNS leak generally means DNS requests are reaching a resolver you did not expect while using a VPN or another privacy setup.
Why DNS matters
Before your browser can connect to many websites, it needs to resolve a domain name. The resolver handling that request can learn which domains are being looked up, although DNS information alone does not necessarily reveal every page or action.
What people mean by a DNS leak
When a VPN is intended to route DNS through its own or another chosen resolver, seeing requests handled by an unexpected ISP resolver can indicate that DNS is bypassing the intended path. Results require context because corporate networks, secure DNS settings and relay services can also affect which resolver appears.
How to check without jumping to conclusions
Connect to the VPN server you want to use, run a DNS leak test, and review the resolver names and locations. Compare them with the VPN provider's documentation or with a test performed while the VPN is disconnected. One unfamiliar resolver is a reason to investigate, not automatic proof of a privacy failure.