Loading AI tools
From Wikipedia, the free encyclopedia
A DNS leak is a security flaw that allows DNS requests to be revealed to ISP DNS servers, despite the use of a VPN service to attempt to conceal them.[1] Although primarily of concern to VPN users, it is also possible to prevent it for proxy and direct internet users.
The vulnerability allows an ISP, as well as any on-path eavesdroppers, to see what websites a user may be visiting. This is possible because the browser's DNS requests are sent to the ISP DNS server directly, and not sent through the VPN.
This only occurs with certain types of VPNs, e.g. "split-tunnel" VPNs, where traffic can still be sent over the local network interface even when the VPN is active.
Starting with Windows 8, Microsoft has introduced the "Smart Multi-Homed Named Resolution". This altered the way Windows 8 handled DNS requests, by ensuring that a DNS request could travel across all available network interfaces on the computer. While there is general consensus that this new method of domain name resolution accelerated the time required for a DNS look-up to be completed, it also exposed VPN users to DNS leaks when connected to a VPN endpoint, because the computer would no longer use only the DNS servers assigned by the VPN service. Instead, the DNS request would be sent through all available interfaces, thus the DNS traffic would travel out of the VPN tunnel and expose the user's default DNS servers.[2][3]
Websites exist to allow testing to determine whether a DNS leak is occurring. DNS leaks can be addressed in a number of ways:
Seamless Wikipedia browsing. On steroids.
Every time you click a link to Wikipedia, Wiktionary or Wikiquote in your browser's search results, it will show the modern Wikiwand interface.
Wikiwand extension is a five stars, simple, with minimum permission required to keep your browsing private, safe and transparent.