In the world of computer security, a denial-of-service attack (DoS attack) is defined as an attempt to make a computer resource run out of the resources and make it unavailable to its intended users. The main aim of Dos is to prevent an Internet site or service from functioning efficiently or at all, temporarily or indefinitely.

We can understand by its meaning that “Denial or service” occurs when either the service is not available or it can not handle any further request. While using some of the services on yahoo messenger we get a message “Service temporarily not available” , the reason could be there is too much load on the server and it can not handle any further request.

What is Denial of Service ?

In Dos, the attacker attempts to prevent regular users from accessing the site or service. By attacking your site the attacker might prevent you from accessing resources like email and even disabling the loading of the site. In short you service is not able to take further request and hence unavailable.

Why Denial of Service occur ?

Routers, servers and network services are made to handle a finite amount of resources at any given time depending on the hardware configuration and power of that machine. If the limit of request surpasses it will start rejecting any further request. So an attacker can just overload the server with such huge amount of request that server crashes or its not free to take any further request.For an example, An attacker can spam you inbox with so many emails that you cross your storage limits i.e your inbox is full and you don’t get any more emails.

DOS Denial

Features of Dos Attacks

• Disrupting service to a specific system or person.
• Disrupting connections between two machines.
• Flooding of network hence rejecting any further request.

Dos can be very powerful tool in the hands of a smart attacker. There are types and ways to prevent it. We have talked about that in the “Types of Dos Attacks and Introduction to DDos”. I hope you enjoyed the post