Denial of service attacks are the most recent form of computer attacks which aim to hinder or destroy e-commerce and e-business being done on the Internet. Denial of service is when attackers try to stop or disrupt legitimate users from accessing information from a certain resource. Put simply it is when an attacker intentionally tries to stop visitors from visiting a website.

There are four main types of denial of service attacks. The first is a flood attack. A flood denial of service attack is where attackers hog the bandwidth to a certain site so that no other visitors can go through. The second type of denial of service attack is when a connection between two machines is interrupted thereby limiting services. The third type of denial of service attack is stopping a specific user from accessing a service, and the fourth type of denial of service attack is when a service is denied to a specific user.

How are Denial of Service Attacks done?

The most common way is to consume limited resources like bandwidth so that no others can use it. Another common way is to fill up disk space with garbage information so that the computer or server can not function. The less common but more dangerous way is when the attacker alters configuration data so that the computer will not function correctly or even open up other security holes. Recently this was done to over 750 western websites by Islamic extremist who were protesting a military action.

How Can I Defend Against Denial of Service Attacks?

The best defense is front end application hardware such as Radware's DefensePro. Firewalls are useless against flood attacks because they get swamped with data. A firewall is designed to stop viruses and Trojans which are small. Front end application hardware is intelligent so it can monitor all traffic in real time. When it detects a flood attack it simply closes down access from the attacker's point of origin while still allowing good traffic through the network. Another advantage to having intelligent defense is that it recognizes when configurations are being altered and can stop alteration attacks before they start or are allowed to do damage.