NAC (Network Access Control)

Network Access Control restricts which devices and users can connect to a network and what they can reach once connected, enforced at the switch port (802.1X), wireless (WPA2/3-Enterprise), or VPN concentrator. Modern NAC integrates posture assessment (patch level, EDR presence) and dynamic VLAN assignment, and is a baseline control for Zero Trust architectures.

Categories: Radio Access NetworkSecurity ControlsIoT

NAC in context

The radio access network is where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations and downgrade attacks; defenses rest on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

Security controls span signaling firewalls (SS7/Diameter/GTP screening), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36.

To place NAC in the wider telecom-security picture, review 1G, 2G, 5G, 6G, A5/0 and AP — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

More from the TelcoSec Glossary

Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.