The basic technical idea of JusProgDNS

JusProgDNS is a so called “nameserver based filter”. Nameservers are a kind of translation service in the internet. If you as a user call e.g. “” in the browser, then your call must find the way through the Internet lines to the data center (server) of the mirror and the texts, pictures etc. from there again the way back to your computer or your Smartphone.

Technically, however, the Internet does not work with plain text addresses such as, but with so-called IP numbers. You can think of these as a personal postal code. For example, Spiegel has the address for So when you call up with your computer, your computer sends the request for data to But how does your computer know that has this IP address?

The Internet has quasi translation services, the so-called “name servers”, for the assignment of readable domain names to IP addresses. Before your computer can send the request to the mirror data center, it must first ask a name server which IP belongs to This is where JusProgDNS comes into play!

JusProgDNS is a smart nameserver with a built-in parental control function.

For example, if your child calls up the child search engine and the child’s computer asks the JusProgDNS name server for the IP address of fragFINN, then JusProgDNS reports back truthfully and the child’s computer can call up the desired web page of the child search engine directly in the fragFINN computer center.

However, if your child then accesses e.g. and asks the JusProgDNS name server for the corresponding IP address of the porn site, JusProgDNS refuses to provide the correct information. Either the JusProgDNS name server claims that has no IP address (this is how it works with encrypted websites / https) or sends back a wrong IP address and thus simply redirects the call to a blocking info page. Since the child’s computer now does not know the correct IP address of the porn data center, it cannot retrieve a web page from there either. This is the basic idea of parental control with JusProgDNS.

Bullerbü instead of Reeperbahn

This is how you can imagine the function of JusProgDNS: Your adventurous child gets the idea to go on a Reeperbahn stroll. You as parents can’t ask him for the way, you would never tell him. So your clever child reaches for the navigation device to get directions. How good that the navi is from JusProg ;-). When your child enters “Reeperbahn” into the JusProg navi, he actually gets directions and secretly sets off for the Reeperbahn. But the JusProg-Navi knows that it is guiding a minor and instead of leading him to the red light paradise, it leads him directly to Bullerbü with the wrong directions.

P.S. When you get wind of your child’s curiosity, take him firmly by the hand and drive together to the Reeperbahn, so that your child can blink into the adult world under your protection and also learn that various dangers lurk here.


What do you have to do for JusProgDNS to work?

Normally computers, smartphones, tablets and other internet capable devices use the name server of your internet provider, e.g. the one of Deutsche Telekom or Vodafone / Kabel Deutschland. This service is part of your Internet access and is therefore paid for.

However, almost all devices with Internet access also offer the possibility to specifically enter another name server instead of the default name server, which then works as a “translation service” from readable domain names into IP addresses.

So to use JusProgDNS you only have to set in the devices used by your children or e.g. centrally in the DSL Box (FRITZ!Box) that you should use the name servers of JusProgDNS.

Nameservers are also called via IP addresses, so to speak the personal zip codes of JusProgDNS. We have an own “postal code”, i.e. IP address, for each age group (for fail-safety even two per age group in separate data centers). You enter this as name server and the protection works.

You don’t have to be a technical genius to enter nameserver IP. With our step-by-step instructions, even You can find device-independent instructions here:

For popular devices we have prepared special step-by-step instructions, you can find them here:

And if you still have questions, take a look at our “Frequently Asked Questions”, which are the FAQ.