How does Network Access Control work ?

Network Access Control or NAC, for short, acts as a gatekeeper for your network to ensure that only authorized users and devices can connect. It does so by verifying identities, enforcing policies, and monitoring activity so that security is maintained while legitimate access is allowed. So, what exactly goes behind the scenes to make that happen? Here’s an overview of how NAC works and why it’s essential for modern networks.

What is Network Access Control (NAC) ?

Network Access Control is a security solution that governs network access by enforcing policies for users and devices attempting to connect to the network. It integrates protocols and processes for data integrity in both wired and wireless environments by allowing only authorized and compliant entities to access the network.

Ensuring Authorized Access: NAC systems verify the identity of the users and devices before they connect to the network. Implementing strict authentication measures ensures that any person or device with no access can’t enter the network.
Maintaining Network Integrity: One of NAC’s primary functions is to block non-compliant devices from accessing the network. This includes devices that do not meet security requirements.

How does network access control operate?

Authentication

NAC systems initiate the authentication process by verifying the identity of users and devices attempting to connect to the network. Common methods include:

The most common and used method is where a user enters a unique username and password to gain access.
Multi-factor authentication adds an extra layer of security to the above method where a user also has to verify the code sent to his mobile/laptop.
Many enterprise environments use the method of digital certificates where a user has to present digital certificates (issued by a trusted Certificate Authority).
The uniqueness of the biometric data of a user can also be used as a way to authenticate himself.

Role of 802.1X

802.1X is a protocol used in network access control that plays an important role in enabling secure authentication. Key features of 802.1X include:

It restricts access at the port level on the network switches, allowing only authenticated devices to connect to the network.
Based on the authentication result, It can assign devices to specific VLANs. This enhances network segmentation and security.
Non-compliant or malicious devices can be isolated from the rest of the network until they meet security requirements.

Endpoint Assessment

NAC performs detailed checks to ensure that the device is compliant before allowing access. This assessment includes:

Operating System Updates: Ensuring the OS of the device is updated.
Antivirus Status: Checking if antivirus software is installed and up-to-date.
Endpoint Configuration: Comparing configurations to security standards.

If a device does not comply with these standards, it will be quarantined or not allowed to access the network at all. This way the chances of vulnerabilities are reduced as non-compliant devices can’t interact with the network.

Policy Enforcement

After authentication of the device and compliant checking, it enforces predefined access policies depending on several factors:

User Roles: Different levels of access based on the user’s position within the organization.
Device Type: Certain policies may differ based on whether the device is a personal laptop, corporate device, etc.
Location: Access can be limited depending on where the user is connecting from.

For instance, guest users might be restricted from accessing sensitive internal resources while employees have broader access rights.

Monitoring and Response

NAC systems provide continuous monitoring of network activity, which includes:

Real-time Monitoring: It tracks all the connected devices to make sure the devices are compliant.
Immediate Response: It can disconnect the non-compliant devices and alert the administrators when any policy violation is detected.

This ongoing vigilance helps maintain network integrity and security by quickly addressing potential threats.

Conclusion

Network access control (NAC) is essential for securing modern networks by regulating access and ensuring device compliance. By adapting to evolving threats, NAC helps protect sensitive data and maintain a secure, efficient digital environment.