What Is Network Access Control (NAC)?

Network access control (NAC), also known as network admission control, is the process of restricting unauthorized users and devices from gaining access to a corporate or private network. NAC ensures that only users who are authenticated and devices that are authorized and compliant with security policies can enter the network.

As endpoints proliferate across an organization—typically driven by bring-your-own-device (BYOD) policies and an expansion in the use of Internet-of-Things (IoT) devices—more control is needed. Even the largest IT organizations do not have the resources to manually configure all the devices in use. The automated features of a NAC solution are a sizable benefit, reducing the time and associated costs with authenticating and authorizing users and determining that their devices are compliant.

Further, cyber criminals are well aware of this increase in endpoint usage and continue to design and launch sophisticated campaigns that exploit any vulnerabilities in corporate networks. With more endpoints, the attack surface increases, which means more opportunities for fraudsters to gain access. NAC solutions can be configured to detect any unusual or suspicious network activity and respond with immediate action, such as isolating the device from the network to prevent the potential spread of the attack.

Although IoT and BYOD have changed NAC solutions, NAC also serves as a perpetual inventory of users, devices, and their level of access. It serves as an active discovery tool to uncover previously unknown devices that may have gained access to all or parts of the network, requiring IT administrators to adjust security policies.

Further, organizations can choose how NAC will authenticate users who attempt to gain access to the network. IT admins can choose multi-factor authentication (MFA), which provides an additional layer of security to username and password combinations. 

Restricting network access also means control of the applications and data within the network, which is normally the target of cyber criminals. The stronger the network controls, the more difficult it will be for any cyberattack to infiltrate the network. 

Network access control comes with a number of benefits for organizations:

1. Control the users entering the corporate network
2. Control access to the applications and resources users aim to access 
3. Allow contractors, partners, and guests to enter the network as needed but restrict their access 
4. Segment employees into groups based on their job function and build role-based access policies 
5. Protect against cyberattacks by putting in place systems and controls that detect unusual or suspicious activity
6. Automate incident response
7. Generate reports and insights on attempted access across the organization