DOS Attack, whats that!

 U might be guessing what this type of attack if u r a home user but any of your kin or relatives is a administrator of some organization that he knows how much difficult it is to identify it & how to stop or prevent it.This type of attack is network based.....

Don't consider DOS which u have heard in windows.This is entirely different from it This DOS means Denial-of-service attack.This attack is generally carried out when the attacker is not able to gain access to the target system.Under this attack,it prevents all the legal users from  using system resources etc.For example,suppose there is  site which requires user name & password for login & it also monitor that any one can attempt to give wrong password for certain account only for certain number of times, after which that account will be locked for a some period of time.so, if cracker knows about this policy of site administrator than he could give wrong password for all user so that that site locks all the users account for a given amount of time.Here attacker motive is achieved & administrator might have to figure ut that this was a attack....

Now, u might be thinking that than all administrator should monitors all the IP address of each pc & check that all attempts r not from same pc.But,attackers/crackers r smarter than u.They use a modified & much advanced type of DOS attack where it becomes difficult for administrator to   identify who r legitimate user & who r not.This attack is called DDOS attack.......

Hey , DDOS means distributed denial-of-service attack.here, attacker firstly attack other pc & compromise these pcs from over the net & make them zombies.zombies means that those pc which have been compromised will launch the attack at particular time or on the commands of the attacker on the target system.now, in this case it ,attack would be from the around the world so it would be difficult it identify the main culprit & prosecute him....