what is DNS & Active diretory ?

service that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address.Active Directory: A directory service from Microsoft that is a part of Windows 2000. It is an implementation of Internet standard directory and naming protocols that uses a database engine for transactional support