RADIUS

RADIUS (Remote Authentication Dial-In User Service) on port 1812 is used for centralized Authentication, Authorization, and Accounting (AAA) management. It helps ensure that users are properly authenticated before accessing network resources. RADIUS is widely used in enterprise environments to manage network access.

What is RADIUS

RADIUS (Remote Authentication Dial-In User Service) is a networking protocol that provides centralized Authentication, Authorization, and Accounting (AAA) management for users who connect and use a network service. Operating on port 1812, RADIUS is essential for ensuring that users are properly authenticated before they can access network resources. This protocol is particularly useful in environments where multiple users need to access a network, such as in enterprise settings, educational institutions, and service provider networks.

Originally developed by Livingston Enterprises, Inc., RADIUS has become a standard in network management due to its robustness and scalability. It supports a variety of authentication methods, including passwords, tokens, and certificates, making it versatile for different security needs. The protocol also provides accounting features, which help in tracking user activity and resource usage, thereby aiding in auditing and billing processes.

RADIUS works by having a client (usually a network access server) send user credentials and connection information to a RADIUS server. The server then authenticates the information against a database and returns a response indicating whether access is granted or denied. This centralized approach simplifies the management of user credentials and policies, making it easier to enforce security measures across the network.

RADIUS runs on TCP and UDP port 1812 and is official IANA port.

Security risk

If port 1812 is open and the RADIUS service is running, it could be a target for unauthorized access attempts. Attackers may try to exploit vulnerabilities in the RADIUS protocol or use brute force attacks to gain access to network resources. Ensuring strong authentication methods and regularly updating the RADIUS server can mitigate these risks.

In our UFW tutorial you can follow instructions how you can configure UFW to close port 1812. Use StackChanges to monitor if the RADIUS port is closed and stays closed. StackChanges will send an alert if port 1812 is open again.