What is Network Access Control? | VMware Glossary

Network access control is the act of keeping unauthorized users and devices out of a private network. Organizations that give certain devices or users from outside of the organization occasional access to the network can use network access control to ensure that these devices meet corporate security compliance regulations.

The increasingly sanctioned use of non-corporate devices accessing corporate networks requires businesses to pay special attention to network security, including who or what is allowed access. Network security protects the functionality of the network, ensuring that only authorized users and devices have access to it, that those devices are clean, and that the users are who they say they are.  

Network access control, or NAC, is one aspect of network security. There are many NAC tools available, and the functions are often performed by a network access server. Effective network access control restricts access to only those devices that are authorized and compliant with security policies, meaning they have all the required security patches and anti-intrusion software. Network operators define the security policies that decide which devices or applications comply with endpoint security requirements and will be allowed network access.