Denial of Service (DoS) attack overview ....



     Am sure you have experienced this sometimes the internet speed is good and you are receiving the bytes but still some pages take long time to open or even doesn’t  allow you to open them at all. You are trying to configure the internet speed but still the page cannot be accessed while other sites are working just fine. On 6th august 2009 twitter was shutdown for hours, millions of users all over the world were not able to access the site due to DoS, so this is a common thing it can occur to your site or any other site out there.
           “a denial-of-service attack (DoS attack) or distributed denial-of-service attack (DDoS attack) is an attempt to make a machine or network resource unavailable to its intended users. Although the means to carry out, motives for, and targets of a DoS attack may vary, it generally consists of the efforts of one or more people to temporarily or indefinitely interrupt or suspend services of a host connected to the Internet.” That is the explanation given in the Wikipedia. But actually what is meant to be said is that simply the service provider is being stressed.  
                For example in the hospital if a single patient keep on coming back to the doctor with different cases every time and the doctor is attending him alone then others will not be able to get the service from the doctor, that is what the hacker does to the server or the site, he is keeping sending multiple request until the server become s stressed and it cannot serve others who are sending request to it. The diagram can explain it clearly.
The attacker in red is the stubborn patient who keeps on coming back to the doctor (server) with different problems (sever requests) and stressed the doctor as the result the doctor will become tired (stressed) and will not be able to attend other patient (users) in the hospital (system). The site which is under DOS attack usually takes time to load and it is running irritatingly slow whenever the user want to access it.

TECH360 Correspondent