DDoS attacks: what they are, why they happen and what we can do about them

Michael PhillipsWhat is a DDoS?

DDoS stands for Distributed Denial of Service. When someone launches a DDoS attack, hundreds (or thousands) of computers and servers around the world simultaneously send traffic to a web server – or most often, a specific site on a server – in an attempt to take the site down by overwhelming the server.

When a site on our network is the target of a DDoS the effect on your site can range from none, to slowing it down, to making it completely unavailable.  The reason for that is DDoS attacks vary in method and severity, and many of them are counteracted before anyone even notices a problem. Others are more intense or sustained or difficult to counteract, and everyone notices those because they can potentially cripple the network.

Why does an attack on a single site affect the entire network?

A sufficiently large attack on a single site can send enough traffic to the network to overwhelm the routers that live at the entrance to our network. The largest measured DDoS at the time I’m writing this was over 400 gigabits per second – that’s 400 billion bits of data. Per second.

To put that in perspective, some of the most massive and expensive network switches available can handle 100 Gbps, and most common switches are built to handle only 1 or 2 Gbps of traffic. That may sound small compared to a 100 Gbps switch, but it’s more than sufficient for most networks. We host tens of thousands of sites, and our average network traffic is around half a gigabit.

So you can see why an attack large enough to overwhelm the switches can affect every site on the network, including the main DiscountASP.NET site, email, Control Panel, helpdesk, etc.

The method for dealing with large attacks is essentially the same as dealing with smaller ones, but the overall impact is naturally worse, since everyone is affected. Attacks on a scale large enough to effect the entire network are still uncommon, but becoming more of a threat every day, for reasons I’ll spell out in a minute.

What does DiscountASP.NET do to counteract a DDoS?

The methods we use to counteract DDoS attacks are varied and have included just about every method available: DDoS mitigation services, intrusion detection devices, null routing, etc. There are a lot of methods out there, but often the most effective thing we can do is be reactive and responsive. Our network is continuously monitored for malicious traffic, and we have direct control over null routing on all of our backbone connections.

When a DDoS targets a specific site, they are relatively easy to counteract. Though more often than not these days, DDoS do not directly target a domain or an IP, so it takes a bit of time to determine the target (and determining the target is necessary to counteract the attack).

In the past we could just throw massive amounts of bandwidth at an attack to absorb the traffic and mitigate the attack’s effect. But that approach has become much less effective as of late. The botnets have become too large, and a rapidly increasing number of the compromised computers are on broadband connections in homes or corporate servers in large data centers.

While there still isn’t any way to prevent a DDoS before it happens, be assured that we react to every incident of possible malicious traffic immediately and respond with whatever methods are likely to be most effective as quickly as possible.

Why do DDoS attacks happen?

There are a lot of reasons, ranging from political protest to personal grudge and a million other reasons in between. Humans launch these attacks and or course humans can be unpredictable and irrational. When we determine the target of DDoS attacks there is often no outward reason why the site would be attacked. So the reason isn’t always obvious.

The problem – and the reality – is that no matter what we do, inevitably some DDoS attacks are going to have an effect on the network, and possibly your site. It isn’t just us, it’s every site and host everywhere, including the biggest sites on the Internet. Unfortunately, if they can take down Microsoft or Amazon, they can take down DiscountASP.NET. It’s something we are all coming to grips with and trying to learn to prevent.

Where to go for information in the event of a large DDoS attack

If you suspect that a large scale attack is happening, you can check our Twitter, Google+ and Facebook pages for updates and information. We will also be moving our community forum to a server outside of our network sometime soon in order to keep that communication channel open in the event of a large attack.

If a DDoS affects your site you can be sure that we are doing all we can to stop it and return the network to its maximum capacity.

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.