Network Access Control (NAC)
What is Network Access Control (NAC)?
Network Access Control (NAC)A set of policies and technologies that authenticate devices and users before granting them network access and continually enforce posture requirements.
Network Access Control combines identity, device posture, and policy to decide whether an endpoint may join a network and, if so, with what level of access. When a device connects via wired switch, Wi-Fi, or VPN, NAC typically uses 802.1X with RADIUS to authenticate the user or machine, profiles the device, and checks posture signals such as OS version, patch state, EDR presence, or certificate validity. Based on the result, the system places the device in an appropriate VLAN or applies an ACL — from full access to a quarantine network for remediation. NAC underpins zero-trust network access by replacing flat, implicit trust with continuous, contextual decisions.
● Examples
- 01
An employee laptop without current OS patches is moved to a quarantine VLAN until it updates.
- 02
A guest phone joins a captive portal SSID and is restricted to Internet-only access.
● Frequently asked questions
What is Network Access Control (NAC)?
A set of policies and technologies that authenticate devices and users before granting them network access and continually enforce posture requirements. It belongs to the Network Security category of cybersecurity.
What does Network Access Control (NAC) mean?
A set of policies and technologies that authenticate devices and users before granting them network access and continually enforce posture requirements.
How do you defend against Network Access Control (NAC)?
Defences for Network Access Control (NAC) typically combine technical controls and operational practices, as detailed in the full definition above.
What are other names for Network Access Control (NAC)?
Common alternative names include: NAC, Network admission control.