Have you ever tried opening too many software programs in your computer all at once? As more and more programs are opened, your computer will get slow. Beyond a certain point, the system will crash and will have to be rebooted before you can use it normally. In a nutshell, this is exactly how the denial of service to attack works. The server is sent so many requests for service in such high volumes that it is simply unable to cope with the same.
Once the bottleneck is created, each and every legitimate user of the service will repeatedly try to access the same. This combined with the request for service made by the hackers, means that the system crashes. The biggest complication with such an attack is that it is virtually impossible to distinguish between a genuine request for service and a hack attempt.
Traditional attempts to secure the computer involve closing those ports which are normally attacked by the hackers. However, if port 80, which is normally used for all http traffic is attacked, the only option left with the service provider is to either refuse service to all or to accept and provide service to all.
This is a reason why such a small problem can assume gigantic proportions and requires complicated infrastructure to keep the problem under control. Simplistic solutions will not work because that would be tantamount to providing what the hacker wants. The basic idea of the attack is not to destabilize the service forever.
The attempt is simply to prevent the service provider from catering to genuine customers and users in a planned manner. It is advisable to keep track of the latest solutions including intelligent protection options that not just controls the traffic but also distinguishes between good and bad traffic to ensure genuine customers are provided service and hack attempts are tackled very quickly.