What is the use of an Access Control List?

Access Control Lists are useful in restricting the users to any resources in your system or the network. The access control lists are also used to restrict the users from accessing any particular resource in the internet too. Access control lists are used in most the popular operating systems in use, like the Windows NT/2000/2003/Vista, UNIX based operating systems, and other operating systems.

You can restrict the users from accessing any file or folder by providing appropriate permissions for that particular user. You can also groups users into a particular category and restrict access to that particular group. This is the popular method of using access control list.

ACL editors are available which allow you to edit the permissions given for a particular system object. In UNIX you can use the ‘chmod’ command in the command prompt to edit the access control to a particular resource in the system.

Proxy servers and caching tools like Squid allow you to block access to a particular website by mentioning the IP address or the website name. It also allows you to restrict access based on the time and the day. By using regular expressions, you can also restrict access to websites that have a particular string in their URL.