DNS Based Web Filtering

DNS based web filtering takes advantage of cloud based technology to provide an Internet content filtering service equally as powerful as hardware or software solutions, but without the capital investment and high maintenance costs of those. As with most cloud-based technologies, DNS based web filtering software is handy and reliable, and extremely scalable.

Any Internet filtering solution has to have SSL inspection so that it can examine the content of encrypted web pages. Whereas SSL inspection can drain CPU resources and memory when included in hardware and software solutions, with DNS based web filtering the inspection process is done in the cloud – thus enhancing network operations.

How DNS Based Web Filtering Operates In order to filter Internet content using a Domain Name Server (DNS), you need to register for a web filtering service. The service provider gives you a browser-based account you log into, submit your external IP address and set your web filtering policy. Then you just redirect your DNS system settings to the service provider´s web filtering service. If you have a range of web filtering policies for different positions within your company, tools are available to link management tools such as LDAP and Active Directory with the web filtering service. It is also possible to put in place a DNS proxy for per user reporting and select from a variety of predefined reports. Alternatively, it is a simple process to set up your own bespoke reports. Due to the way in which DNS based web filtering works, it can be applied with every type of network and operating system. Multiple locations and domains can be managed from one management portal, and – due to the SSL inspection process being conducted in the cloud – end users will not suffer the latency usually associated with hardware and software solutions.

Highly Granular Controls Maximize Your Security Strength The most common given reasons given for adding an Internet content filter are to safeguard the company from web-borne dangers and to enforce acceptable use policies. DNS based web filtering achieves both these aims by deploying a three-tier mechanism for filtering Internet content. The three tiers work in tandem to maximize the company´s defenses and prevent users accessing material that could be an obstruction to productivity or cause offense. The first tier includes SURBL and URIBL filters. These are commonly referred to as blacklists and they compare each request to view a website against IP addresses from which malware downloads, phishing attacks and spam emails are known to have been initiated. When matches are located, the request to visit the website is denied. Blacklists are given and updated by your service provider. Behind the blacklists, category filters and keyword filters make up the second and third lines of defense. These can be applied by system administrators to stop users visiting websites within some categories (social networking for example), or those likely to include material that would be inappropriate for an office environment. Keyword filters can also be used to prevent users accessing specific content or web applications, or downloading files with extensions most linked with malware. Exemptions to general policies can be set up by user or user group if access to a website or web application is required by a certain department within the company. For example, you may not want your employees to engage in personal Internet banking during working hours, but it is likely crucial for your finance department has access to online banking services. Similar exemptions could be established (say) if your marketing department needed access to the company´s Facebook or Twitter accounts.