A directory service is basically a network service that is capable of storing resources that will then available for the user to use such as e-mail addresses and devices like printers. Also the directory stores permissions and accessible rights for the users also it can make it easier if you wanted to access a different server you could would be able to via the server name as oppose to typing in the whole IP address. On many occasions more than one server is used the reason behind this is that it can speed up a process such as searching for someone credentials if a user for the school can log on to the network this will searched what the user typed in on the database and if it is a big school it will be quicker rather than all the students data on one server.
Active directory
Active directory is a directory service which is built-in most server operating systems. It is responsible for authenticating all users and computers on the network and putting up security policies for all computers within the network as well as installing or updating to the latest software. It is also the main location for network administration and security such as when a user logs into a computer within the network Active directory identifies whether this person is a normal user or the system administration. All this is done by the domain controller which is the server and it basically handles the authentication management. When you log in the information is checked by the domain controller this is done for the user as well as the computer. If they are not on the database then they will simply not be allowed to access the network. A perfect example is a student trying to log onto the school network. DNS this is Domain name server and basically translates domain names into IP addresses. When the active directory is in use the DNS use the computer and checks by its DNS and if its DNS is on the database then it is allowed to connect to the network and if it is not allowed then the device would not be allowed onto the network.
Also when there is new students that join the school they will need to have credentials created to allow them to log on and access the network. They would also have a default username which can never be changed and password which they can change, also in our particular school as soon as a student has left the school and after a year they are removed from the database which frees up space on the server for the new Year group. Also in our school these are separated into particular groups which is year groups and these are identified by the year that they account was created for example if a student joined the school 2009 then there log In would be 09 then there surname.
