NxFilter is a DNS filtering server that is capable of filtering Internet traffic based on domain names and content categories. In addition, it can use DNS packet inspection to protect your network from malware and botnet activity.

NxFilter is installed on a single PC, where it acts as a DNS proxy server. In order to route your Internet traffic through NxFilter, you will need to change the DNS settings on all machines that you want to protect to use the IP address of the NxFilter instance (instead of your regular DNS servers).

Each machine that uses the NxFilter server in their DNS will be automatically protected based on your global or user based settings. You can configure the filtering options from a browser based interface (Default password: admin) that also provides statistical charts and detailed reports.

NxFilter supports multiple content policies can automatically apply a certain policy to a specific user. You can also create content categories that allow you to group multiple domains into a category that can be blocked or quota limited. NxFilter can also be integrated with AD/LDAP.

The easiest way to block content by category is to download a blocklist from ULRBLocklist.com (see documentation), which allows you to quickly add dozens of pre-configured categories with almost 2 million websites.

NxFilter works well and offers flexible filtering options, however you should have some basic network knowledge to properly install and configure all options.