What is acl - Access control list - How acl works

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Access Control List - ACL

Introduction to ACL - Access Control List

ACL is part of computer file system, which helps in assigning the user’s access to the content of the file. A computer file is a reserve for sharing and storing information regarding computer programs in computer memory. There are two types of access control lists one is file based and the other is network based.

The file based system is like a table which contains the pertinent information regarding the authoritative users which can access the programs, files and processes of a specific system. While in network based ACLs this term is used to describe the rules, which allow the hosts and network to use the network services.

Working of ACL

ACL is a table which guides an operating system regarding the right of users to the resources of the computers such as computer directory. Every object possesses some security attributes that also control the ACL. This list determines the access privileges for the users. To clearly state let us divide it into three broad categories like which users are given the right to read the file, which can write to file and which can execute the file. However the exact implementation is dependent upon the use of different operating systems available in the market. Some of the most common softwares are Microsoft Window’s NT 2000, Novell’s NetWare and open VMS from digital. Let’s demonstrate the working of ACL by deploying NT 2000.in NT 2000 ACL is attached to the system. Every ACL contains some access control entries, which NetWare contains the record of users. For this user group their assigned roles and access privileges are stored on a sequence of bits which is referred to as an access mask. Programmer is sometimes also known as an object administrator is authorized to compose ACL.

Significance of Access Control Lists in Network

The most desirable feature of ACL is its key to provide security to the network. The access lists help in providing basic level network security. ACL provides traffic flow control moreover it can also limit the routing updates. The importance of ACL can be judged from the fact that if there is no ACL working in your network all data frames would spread over all the network paths and hence the flow of traffic would be troubled. Access lists can be used allow one specific host to utilize some of the network resources. The ACL would hamper the entry of another host to that specific area. Imagine a network with host A prevented to access the human resources network and host B is allowed with an access to human resources network. The ACL will make sure that only the concerned host will communicate with the HR network which in this case is host B.ACL can be configured for all routing protocols. The working of the router is greatly monitored by ACL list, because it is in this list that which datagram need to be transferred and which to be discarded.

ACL Security

Whenever any operating system receives a request from any user to perform an operation over the file system, it compares the request with the access list in order to determine if the operation is approved. If the list contains the user identification to perform the desired operation it is allowed to work. The ACL security system is really complex because thee are many core issues which need to be addressed like how the ASL can be edited , which processes can be modified and which new user is assigned access. The file based security can be set using group or user ID. The major benefit of using ACL is that if you replace your current operating system with any other OS like Windows with LINUX some of the workstations would still work under new operating system