Frequently Asked Questions


No Refract DNS is not a fully featured DNS Server and isn't designed to be. Refract DNS is designed to remove the day to day headaches IT professionals have with managing their Windows hosts file.
No Refract DNS does not edit the Windows hosts file except during the import process. Refract DNS uses a Windows service to respond to DNS requests and maintains its own configuration. You can still place entries in the Windows host file if you wish.
To test changes to your configuration we recommend using NSLookup. This is a tool installed on most Windows computers. When testing international domains with NSLookup you will need to use the punycode version of the domain name instead of the real domain name. You can access the punycode version of the domain by right click on the record in Refract DNS.
Refract DNS works by overriding the DNS server used by the network interfaces on your computer. This can be configured either to be automatic or manual. For Refract DNS to work a network interface must be active, i.e. connect to a network (it does not require access to the internet). If you are not connected to a network then Refract DNS is unable to respond to DNS requests.
All you data is stored locally on your computer. No configuration data (IP addresses, domains, blacklists, groups, settings) is stored remotely. At all times you are in control of your data.


When you setup Refract DNS for the first time you need to specify the Upsteam DNS server that will handle DNS requests that Refract DNS itself cannot handle. By default the DNS server used is the Google Public DNS servers at and If your company has internal domain names you need to add your internal DNS servers to the upstream DNS list in Refract DNS. You can do this using the Settings page.

Third Party Applications

Many web browsers have an internal DNS cache. When the IP is changed in Refract DNS the change may not be instantly reflected in the web browser because of this caching mechanism. You can find out more about specific browsers on this page.
Firefox allows the user to control the length of time it caches DNS information. To set the cache time perform the following steps:
  • Open a new tab and go to about:config
  • Search for network.dnsCacheExpiration
  • If you don't have it, add it (right click "new Integer")
  • Set value to your desired setting.
Chromes internal DNS cache timeout cannot be set. Instead the cache must be manually cleared or you must wait for the normal timeout. Additionally you may need to close any open sockets to force Chrome to re-establish connection with the remote server using the new IP. For information on how to do this see How To Geek

A user will see this error if another application is using UDP port 53 or TCP port 53 on you local machine. Only one application can bind to these ports at a time. If Refract DNS cannot bind to these ports it cannot function.

To find the application that is using these ports perform the following steps:

  1. Open a Command Prompt in Administrator mode.
  2. Enter the following command to list UDP ports:
    netstat -anob -p udp
  3. Search for Port 53. The image below shows Refract DNS is using Port 53
  4. The label beneath the IP/Port combination indicates which application is using the port.
  5. Enter the following command to list TCP ports:
    netstat -anob -p tcp
  6. Search for Port 53. The image below shows Refract DNS is using Port 53
  7. The label beneath the IP/Port combination indicates which application is using the port.
  8. To allow Refract DNS to access the port you need to stop the applications using these ports.
  9. After stopping the other application restart the Refract DNS Windows Service.


When you purchase Refract DNS you can download and use any updates released within 1 year of purchasing your license.

Remove the frustration of the Windows hosts file and take control of your DNS.

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