Ethical hackers typically have very strong programming and computer networking skills and have been in the computer and networking business for several years. They are also adept at installing and maintaining systems that use the more popular operating systems (e.g., UNIX** or Windows NT**) used on et systems. These base skills are augmented with detailed knowledge of the hardware and software provided by the more popular computer and networking hardware vendors. It should be noted that an additional specialization in security is not always necessary, as strong skills in the other areas imply a very good understanding of how the security on various systems is maintained. These systems management skills are necessary for the actual vulnerability testing, but are equally important when preparing the report for the client after the test.