How does this DNS-leak-detection site discover which DNS server is being used?
by Ulysses_ from LinuxQuestions.org on (#55P8W)
Have set up a gateway with an intercepting SOCKS 5 proxy that sends everything through Tor, including DNS over TCP (DNS over UDP is disabled by truncated answers that force TCP to be used).
The following site tests for DNS leaks. It says: "This test attempts to resolve 100 randomly generated domain names asynchronously".
https://browserleaks.com/dns
Given the test runs in the browser, how does it discover which DNS servers the 100 queries go to? Whatever is set as the DNS server in the network manager is easy to discover but irrelevant because all DNS traffic is intercepted. If you just type:
dig google.com
you do not get to know the DNS server really being used. How can the site's script find out?
The following site tests for DNS leaks. It says: "This test attempts to resolve 100 randomly generated domain names asynchronously".
https://browserleaks.com/dns
Given the test runs in the browser, how does it discover which DNS servers the 100 queries go to? Whatever is set as the DNS server in the network manager is easy to discover but irrelevant because all DNS traffic is intercepted. If you just type:
dig google.com
you do not get to know the DNS server really being used. How can the site's script find out?