The Value of a DNS Firewall


Network security has become a high priority subject for both the enterprise and the home user of late. The seeming non-stop parade of high-profile data breaches has left most IT professionals with no choice but to put the protection of their networks and their data at the top of their to-do list.

Everyone has heard the term "firewall." While it is possible to dramatically improve the security of your network with basic firewalls attached to your critical servers and public-facing network interfaces, there is more to firewall protection than just the standard choices. It is time you consider a DNS firewall.

What is DNS?

The Domain Name System is the Internet protocol that allows network-connected clients and servers to translate Internet Protocol or IP addresses to domain names like yoursite.com DNS operates on a network of machines called nameservers, which maintain lists of registered domain names and the addresses where the machines that serve data associated with those domain names reside.

What is a Firewall?

A firewall is a piece of hardware or software that analyzes incoming and outgoing network traffic and either permits or forbids its routing based on a set of pre-determined rules. For example, if your firewall is set up to disallow traffic from this.com and to allow traffic from that.com, then the computer or computers on your network will be able to access that.com but will not be able to access this.com

Firewalls can have very specific and granular rules, and can be very effective in denying access to potentially malicious traffic.

DNS Firewalls

A firewall based on the DNS protocol simply organizes its rules such that all traffic is categorized by either domain name or IP address. So if a router, for example, were to set up a black list of sites and organize them by domain name, it would qualify as a DNS firewall. It would also qualify if it organized those sites by IP address.

Black and White

A black list is the list of sites that are not allowed to connect to a network. Any site not on the list may connect. By contrast, a white list is the opposite. All sites on the list may connect. All other sites may not.

The Value of a DNS Firewall

The reason these kinds of firewalls are so useful is because they allow a network to block or allow traffic based on individual domains. This means any site identified as a possible source of malware or destructive traffic can be added to the black list and prevented from connecting to either the router or any machine on the network.

DNS firewalls and standard firewalls interlock, so very often the kind of potentially dangerous traffic that manages to overcome a standard firewall will be blocked by the DNS firewall's black list or white list.

With security becoming an ever-greater issue, DNS firewalls should be on your list of possible enhancements to your network's security. To learn more, please visit the www.bluecatnetworks.com website.