Default Prefix - A definition

The Default Prefix refers to a setting in the Windows registry, which specify how domain names that does not begin with ftp, gopher, home, mosaic and www are prefixed. By default, the Default Prefix is set to 'http://'. For example, if you enter 'kephyr.com' in your Internet Explorer browser it will be replaced with the 'http://kephyr.com/' URL.

This setting in the registry can be used for both good and bad and many browser hijackers employ this to redirect web traffic through their web site where they can open pop-up windows or show other types of advertisements and then redirect you to the site you were going to in the first place. For example, CoolWebSearch.ehttp utilize this technique to prefix 'http://ehttp.cc/?' to domain names entered in the Internet Explorer address field. When you enter kephyr.com in your browser, you end up at 'http://ehttp.cc/?kephyr.com' for a fraction of a second and then they redirect you to 'http://kephyr.com/'.

The Default Prefix is located in the registry under 'HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows \ CurrentVersion \ URL \ DefaultPrefix \'.

Reset the Default Prefix manually

To reset the Default Prefix settings, follow the instructions below, which includes minor modifications to the registry.

1. Start the registry editor. This is done by clicking Start then Run. (The Run dialog will appear.) Type regedit and click OK. (The registry editor will open.)
2. Browse to the key:
   'HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows \ CurrentVersion \ URL \ DefaultPrefix \'.
3. In the right pane, right-click the '(Default)' value and modify its data to 'http://'
4. Exit the registry editor.
5. Close all Internet Explorer browsers.
6. Your browser should now have the default WWW prefix, and you can verify this by entering 'kephyr.com' in the Internet Explorer address field. The domain name should be replaced with the http://kephyr.com/ URL.