Secure Your Network with DNS Filtering Services

DNS stands for Domain Name System, which is the protocol on the Web that converts a text name for a Web address into an IP address. As inferred from the name, DNS filtering is an application that filters DNS requests, blocking some requests while permitting others to proceed. When accessing a filtered site, the filter can redirect an unauthorized user to another page, usually a “you are not authorized…” message, or simply dropped (“Page not found” error).

IT staff can apply DNS filtering to inbound Internet traffic, outbound Internet traffic or both. Organizations filter inbound traffic for two main reasons. First, as a security measure, where requests from unknown or suspicious addresses are blocked from accessing the URL (uniform resource locator, or simply Web address), belonging to the organization. Second, some organizations use DNS filtering to permit access to certain locations based on the origin address. For example, a company sets up a paywall where users who pay a fee have access to additional content. On the outgoing side, organizations typically use DNS filtering to prevent staff access to questionable locations or to restrict access to non-business locations, such as social media. An organization can also use DNS filtering as a tool within its IT environment to control user access to organization information. The organization can set up an intranet with address-based data locations and then control user access through DNS filtering.

Typically, IT staff sets DNS filters according to standard logic rules (allow anyone from these address to access this location, allow anyone except these addresses to access this location). Most filters support multi-variable criteria (“AND” and “OR”, for example). In addition to web addresses, most filters can also add a time dimension (for example, “company staff cannot access social media sites during standard work hours”) or a class dimension (for example, “Silver Partners can access these sites in our network, Gold Partners can access Silver sites and additionally these sites”)