Denial of Service testing is done on systems to check whether they would withstand such an attack launched over the network targeting them. Denial of service attack affects the system ability to provide services to clients thus causing harm to system and clients. There are two factors for DoS, one is intentional and other is unintentional. In intentional case the system is targeted for vested interest and in unintentional case system receives higher then expected request from clients. Auditor measures the security of system by checking administrator account, system files and their access privileges. The access privileges to system by other networks are examined. The access privilege to system files and folders by clients and staff members must be well defined.