Network Access Control: Securing Organizational Networks

As organizations grow increasingly reliant on technology and networks to operate their business, protecting these critical systems from potential threats becomes ever more important. One of the key tools used by companies to secure their internal networks is Network Access Control (NAC). NAC provides automated control and management of devices connecting to and disconnecting from an organizational network. By implementing robust NAC policies, businesses can help ensure only authorized devices are granted access and potential security risks are mitigated.

What is Network Access Control?
In its simplest terms, Network Access Control is a set of technologies that monitor and control devices’ access to an organization’s internal network. NAC solutions work to identify users and devices attempting to connect, assess the security posture of those systems, and either grant or deny access based on pre-defined policies. This helps enforce an organization’s security requirements and quickly alert staff to unauthorized devices that may pose risks.

The core components of most NAC solutions include network access devices that monitor traffic at connection points, an authentication server to validate users and devices, and a policy server to determine compliance and access control decisions. Technologies like 802.1X port-based network access, guest Wi-Fi portals, and agent-based assessments are commonly used alongside NAC to help identify and control network access. Together, these capabilities automate the previously manual process of verifying security configurations before granting access to internal business systems.

Securing Network Access Points
One of the primary functions of NAC is securing an organization’s main network access points like wireless access points, switches, and remote/DMZ networks. By placing network access controllers or sensors at these entry points, NAC continuously monitors all devices attempting to connect. It can identify devices by their MAC addresses, asset information, operating systems, patch levels, antivirus status and more. This visibility helps control and segment access based on the type of device and its security posture.

For example, personal devices like employee phones and laptops may be allowed basic internet access after authenticating via 802.1X or a captive portal. But full network connectivity would require the devices to meet policy checks like having endpoint protection installed and being up to date on patches. Any non-compliant devices could automatically be placed in a limited access “quarantine” network until passing security scans. This prevents unvetted or vulnerable systems from reaching internal business servers and sensitive company data.

Assessing and Onboarding Guest Devices
A modern NAC solution also helps facilitate secure guest access and BYOD usage. Guest portals with terms of use agreements and onboarding questionnaires allow organizations to gain visibility into guest-owned devices. They can identify the device types, operating systems, and intended use before provisioning limited or temporary access. Devices are checked for security risks, and potentially sensitive guest traffic can be steered to isolated guest subnets.

For employee and contractor devices, NAC expedites the onboarding process through automated access provisioning and security configuration checks. Upon connecting to the network, devices are directed to registration portals where users can authenticate. The NAC then performs configuration assessments and automatically applies necessary security policies, certificates or VPN configurations before fully integrating the device on the network. This streamlines bringing new systems on board while still enforcing security baselines.

Continuous Monitoring and Vulnerability Scanning
In addition to controlling initial access, NAC solutions provide continuous monitoring of all devices connecting over time. Agents on endpoints report system information, patching levels, running processes and more back to the NAC servers. This enables post-access policy checks to ensure devices still meet compliance standards over time as changes occur. If vulnerabilities or abnormal behavior is detected, automated remediation actions can isolate the compromised systems to limit potential damage.

To supplement agent-based checks, standalone network vulnerability scanners integrate with NAC deployments. On a scheduled cadence, scans assess device security configurations from the network level without requiring agents. Any newly discovered vulnerabilities can trigger quarantining of affected devices until patching. Together, ongoing monitoring and periodic scanning helps find and fix weaknesses before attackers can exploit them. It serves as a active defense that reduces the attack surface within the organizational perimeter.

As digital transformation accelerates across industries, the need to secure expanding IT infrastructures becomes ever more pressing. Network Access Control provides enterprises a central way to enforce consistent security policies across all systems connecting to their environments. Automating identity verification, access control, vulnerability monitoring and more through NAC streamlines securing network perimeters. When properly configured and deployed, it delivers improved visibility and control over devices while reducing workloads for stretched IT teams. As threats grow increasingly sophisticated, NAC remains a foundational tool for holistically protecting today’s technology-reliant operations.