The browser (typically) provides the operating system with a name, and expects an address.
Let's say that, when this happens (dnsapi.dll in windows; query.c in reactos source code, function DnsQuery_A or DnsQuery_W), the name is checked against a "rule" file or registry setting. (My background is strong in Linux / Unix, so I'm going to explain using the 'file' method).
The structure of that file might look like this:
Code: Select all
Block host1.domain1.example.com Block *.domain2.example.com Log Block malware.domain.net Allow *;
A "blocked" request could be returned some sort of "permission denied" error.
Overall, the goal is to give computer administrators greater control over DNS. Would it be useful? I would appreciate such functionality on my OS.
How difficult would this be to implement? I've looked into doing this on Windows, but as Windows is closed source, getting something like this to function reliably (hooking anyone?) seems difficult.