PHPJabbers' FREE Password Protect Content script uses MySQL database to store all contents (texts, images, multimedia, etc.) that you need to protect. You set a password for each block of content. When visitors open the respective web page, they will see a password box. After they enter the password, the content will be displayed. This is a quick and efficient way to protect small parts of your web page content.

Magento GEOIP IP, Country Block Extension by FMEExtensions allows you to filter traffic to your website based on the IP address of visitors. You can monitor online traffic and block unwanted visitors.

This GeoLocation IP blocker module allows you to block access to your website or a part of it from any location. You can block a country, IP, or a region from accessing your site.

Another great thing in this plugin is that you can create and configure rules to automate your website security....

GEO IP Magento Store View Switcher Extension allows you to redirect store/website based on GEOIP. You can create stores and configure them for specific target audience. This Geo location module uses Maxmind database so that you can select desired region/country easily.

Once users land at your site, they can manually switch to any other store/website. Admin can enable links in the header and footer for this functionality.

Learn more about this module on Magento Connect.