HOW THE NET PURIFIER WORKS
How it work is pretty simple, only redirecting DNS queries from user devices to our DNS servers. Redirections can be obtained using dstnat in any kind of Router or Firewall, or by change DNS Server (and port) in user devices, or using DNS client softwares such as Dnsmasq, Bind, Unbound, Powerdns, ...etc in user devices
Users can choose filtering level by redirecting DNS queries to specific port of our DNS Server. List of available ports and filtering levels can be read here.
Blocked sites will be answered with NXDOMAIN, or NO-DATA, or 0.0.0.0, or 127.0.0.1, or other answers, depending on the category that is triggered and how the server is configured.
A small TTL of one minute (60 secs) - or other values (depends on how it configured in server) - forced on every blocked sites, except DDOS will be forced with TTL one day (86400 secs).
Free Server only accept query-type: A, NS, TXT, PTR, and MX. Other query types will be ignored with reply NO-DATA. Free Servers are highly anonymized, placed behind common public DNS servers.
There is a limitation queries per second on Free Server, but fair enough for home network that have only few devices connected. While for network with many devices connected, such as internet hotspot for public or school, better using our Commercial Services.