Originally Posted by md usa spybot fan
How Spybot Search & Destroy protects against the installation of Spyware/Malware
An ounce of prevention is worth a pound of cure.
There are four levels of protection currently offered by Spybot S&D.
The first level of protection is immunization (a passive protection). When you “Immunize”, entries are added to the system Registry. This blocks cookies from some sites, places other sites in the restricted zone and blocks the download/execution of selected ActiveX scripts. Also Note: If you use Spybot S&D and other products like SpywareBlaster, etc. together, there is an overlap of some of the protection offered. If you undo or disable the protection in one product, it may remove some of the protection installed by the other. You should re-immunize or re-enable the protection in the other products as appropriate.
The fourth level of protection is through the addition of HOSTS file entries. This is a passive protection. The HOSTS file contains the mappings of IP addresses to host names and is loaded into memory at startup. The HOSTS file must contain one entry: "127.0.0.1 localhost". The IP address 127.0.0.1 is the local machine. Windows checks the HOSTS file before it queries any DNS (Domain Name System) servers, which enables entries in the HOSTS file to override addresses in the DNS. Adding an entry such as “127.0.0.1 malware.com” to the HOSTS file prevents the access of “malware.com” through IE because any connection attempts are redirected back to the local machine. HOSTS file entries can also be used to block other applications from connecting to the Internet.