Blocking Unwanted Parasites with a Hosts File - The Hosts file contains the mappings of IP addresses to host names. This file is loaded into memory at startup, then Windows checks the Hosts file before it queries any DNS servers, which enables it to override addresses in the DNS. This prevents access to the listed sites by redirecting any connection attempts back to the local machine. Another feature of the HOSTS file is it's ability to block other applications from connecting to the Internet, as long the the entry exists. (2032 hits)