Small Business Defense – Detect, Avoid, Leverage Business Relationships
If you’re dealing with a DDOS attack, I’m afraid that I haven’t much good news for you. Once it’s started, it may be a bit late to try to deal with it. Odds are, you’re best off just waiting it out. Failing that, you can try to change IP addresses on your external systems, however, that technique is less effective than it was and requires the assistance of your ISP.
No, the right way to handle this sort of attack is long before it starts.
These sorts of attacks tend to start a bit slowly, and can be recognized by a ramping up of traffic. However, in order to detect it, you have to first know what legitimate traffic looks like. Thus, for months before the attack, you have to be watching what’s coming in. You should know what “normal” looks like, so you can detect “abnormal”. Not only will this help you differentiate an attack from simply outgrowing your resources, but it will also help you identify how you are using your resources so you don’t waste your money.
Bear in mind that most Internet connections can only carry so much, and if your employees are using it watching YouTube videos, that leaves less for legitimate customers. The first rule is to know what you have and how it’s being used. To reference Tuesday’s post, you need to know how many rats are normal, so you know when you’re about to have too many of them.
Then, you can move on to attack avoidance. There are systems out there that are specifically designed to handle DDOS attacks, but let’s assume that you don’t want to pay for that. One quick solution is to use a set of proxies. These can be servers or network devices in a proxy configuration. The way these work is to simply receive connections and then balance them to the back-end server. Here, you can set up rules to drop illegitimate traffic to reduce what goes through to your server to a manageable amount. There are many technical ways to do this, and none of them are perfect… however, you don’t need perfect. You just need to drop enough traffic to get things working again. (In other words, you don’t need to stop all the rats, you just need to make sure that there’s enough grain for you and your family to eat.)
However, this solution only works assuming that the attack is somewhat small in scope. If the amount of traffic is overwhelming and your connection itself can’t handle it, having a set of proxies won’t help you much. You’ll need to call your ISP. This is why it’s good to have a good business relationship with your ISP. You should know the names and numbers of who you need to call, and you’ll need them to be technically competent. Ideally, you should be able to call them up, and say “I think I’m having a DDOS attack, can you block all traffic from Asia” (assuming that you don’t do business in Asia, of course :). This is like asking for international help in the face of a massive influx of rats.
The huge ISPs tend to have the technical skill, but lack the personal relationship. The really small ISPs will bend over backwards to help you, but may not know how. I suggest going for the middle of the road approach. Interview prospective ISPs and ask how they would handle this sort of situation. Ask if they can give you an emergency number that would always have a live person answering, 24×7. The good ones will, though they might charge you when you call after hours. This is well worth it.
In the end, you will have built an infrastructure that is resistant enough and built a business relationship that is flexible enough. The only way to be 100% protected against this sort of attack is to have more resources than the rest of the Internet combined, and that’s just not going to happen. This sort of preparation is fairly cheap, and worth a lot if you need to leverage it.
In the end, it’s cheap insurance.