In our first blog about Distributed Denial of Service (DDoS) attacks and small service industries, we discussed measures that organizations should take to prepare themselves for DDoS attacks. In this second installment, we will go over some methods that are useful in defending networks from these attacks. (The third and final installment in this series will deal with responding to DDoS attacks).

One good way to defend your network from DDoS attacks is to hire a service organization that specializes in the problem. They typically employ algorithm-based firewalls, large networks, monitoring, and other techniques to thwart these attacks, and can be very effective. However, these services are also pretty expensive and impractical for smaller organizations unless the threat level is very high indeed. The good news is that you can do a lot to defend yourselves from DDoS attacks.

The first step is knowing exactly what it is that you are defending. Computer networks tend to grow organically and it is a sad fact that most organizations have a very imperfect picture of how their networks are set up and how they behave. To defend against DDoS, it is important to know what typical network traffic looks like throughout the business year. This helps you set proper thresholds for automated detection devices and ensures quick detection of the onset of events such as DDoS attacks.

Another step you can take to help defend against DDoS attacks is to consider a cloud-based approach for your web services. With the traffic volumes DDoS attacks can currently generate, internal web servers at smaller organizations are sure to be overwhelmed. But by employing a content distribution network in a cloud setting you vastly increase your capacity, reduce the chance of any one server becoming unserviceable and are able to deal with the event more efficiently.

It is also important to work with your Internet Service Provider (ISP) during DDoS attacks. Your ISP could help in many ways including source blocking, scrubbing, load distribution and rate limiting. In addition, it should be remembered that many DDoS attacks are launched as diversions to cover up other attacks against organizations. Ensuring that your network is properly enclaved and monitored can go a long way in protecting your information and control assets during these attacks.

This series is written by John Davis, MicroSolved, Inc.