In short: no. There's no way to completely protect your network from denial-of-service attacks, especially with the prevalence of distributed denial-of-service (DDoS) attacks on the Internet today. It's extremely difficult to differentiate an attack request from a legitimate request because they often use the same protocols/ports and may resemble each other in content.
However, there are some things you can do to reduce your risk:
- Purchase a lot of bandwidth. This is not only the easiest solution, but also the most expensive. If you simply have tons of bandwidth, it makes perpetrating a DoS attack much more difficult because it's more bandwidth that an attacker has to clog.
- Use DoS attack detection technology. Intrusion prevention system and firewall manufacturers now offer DoS protection technologies that include signature detection and connection verification techniques to limit the success of DoS attacks.
- Prepare for DoS response. The use of throttling and rate-limiting technologies can reduce the effects of a DoS attack. One such response mode stops all new inbound connections in the event of a DoS attack, allowing established connections and new outbound connections to continue.
DoS protection is more art than science, requiring a combination of techniques to limit the impact of such an attack on your organization. Good luck!
For more information:
- Get further advice on preventing DoS attacks.
- Looking to prevent distributed denial-of-service (DDoS) attacks? Read more.
This was first published in June 2009