Quad9 is a free security solution that uses DNS to protect systems against the most common cyber threats.

Its is developed in collaboration with IBM, Packet Clearing House and Global Cyber Alliance.

How it works?

Quad9 routes your DNS queries through a network of servers wich uses threat intelligence in order to give a real-time perspective on what websites are known to include malware or other threats: if the system detects that the site is known to be infected, it will automatically block the entry.


What about privacy?

From Quad9 Website:

When an entity or an individual is using the Quad9 infrastructure, their IP address is not logged in our system. We, however, log the geo-location of the system (city, state, country) and use this information for malicious campaign and actor analysis, as well as a component of the data we provide our threat intelligence partners. 

We store details of the DNS records queried, timestamp, and the city, state, and country from where the query came. We do not store source IP information of end user queries. 

How to setup Quad9 DNS

Microsoft Windows

  • Open Control Panel, select Network and Internet, and then select Network and Sharing Center. Click Change adapter settings on the left pane.
  • Right click the network interface connected to the internet, and select Properties. Select Internet Protocol Version 4 (TCP/IPv4) from the list and click Properties.
  • Select “Use the following DNS server addresses” and type into the Preferred DNS server box.
  • Click OK then Close to save your settings.


Apple OsX

  • Go to System Preferences and select Network Settings.
  • Click Advanced and select DNS.
  • Click the "+" sign and add "" at the top of the list.
  • Click "Ok" then "Apply" to save your settings.



Edit the file /etc/resolv.conf:

$ sudo nano /etc/resolv.conf  or $ sudo vim /etc/resolv.conf

Edit/append as follows: