The Windows host file is a plain text that Windows uses to map hostnames to IP addresses, like a DNS resolver. The contents of the host file are always at a priority level higher than other domain resolving methods. Because of that the host file is often used by network administrators to define domains on a LAN or rerouting traffic. It is also the easiest method to block websites, Internet ads and other contents across all browsers.
The host file is tucked away deep inside the Windows directory. The actual location is %SystemRoot%\system32\drivers\etc\, which is deep enough to access if used frequently.
Portable WinHosts is a small portable application that makes it easier to edit the Windows host file. You can add new entries to the file or delete old one. Simple and easy.