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Why RADIUS is ignoring requests to authentication address?

Ubuntu 13

Introduction

RADIUS (Remote Authentication Dial-In User Service) is a client/server protocol and software that enables remote access servers to communicate with a central server to authenticate dial-in users and authorize their access to the requested system or service. However, there are instances where RADIUS may ignore requests to an authentication address. This article will delve into the possible reasons and solutions for this issue.

Understanding the Issue

When attempting to authenticate with the IP address, the server may not respond, and the logs may show an “Ignoring request to authentication address” message. This essentially means that the RADIUS server is not recognizing the requests coming from the specified IP address. This issue could be due to various reasons such as incorrect configuration settings, firewall settings, or the RADIUS server not listening on the correct IP address.

Checking the Configuration

One of the first things to check when encountering this issue is the configuration in the clients.conf file. This file contains the definitions of RADIUS clients that are allowed to use the server. Each client IP address needs to be correctly defined with the correct shared secret.

Here is an example of how the entry should look:

client 192.168.2.218 {
 ipaddr = 192.168.2.218
 secret = testing123
}

In the above example, 192.168.2.218 is the IP address of the client, and testing123 is the shared secret. The shared secret is used to encrypt and decrypt the communication between the RADIUS server and the client.

Checking Firewall Settings

Another common reason why RADIUS might ignore requests is due to firewall settings. The necessary ports (1812 for authentication and 1813 for accounting, by default) need to be allowed through the firewall.

You can allow these ports using the following commands:

sudo ufw allow 1812
sudo ufw allow 1813

In these commands, sudo is used to execute the command with root privileges, ufw is the Uncomplicated Firewall, and allow is used to open the specified port.

Verifying the RADIUS Server Listening Address

It’s also important to verify that the RADIUS server is listening on the correct IP address. This can be checked in the radiusd.conf file under the listen configuration.

If the issue persists, it may be helpful to examine the output of sudo freeradius -X for any error messages or warnings that could provide further insight into the problem.

Conclusion

RADIUS ignoring requests to an authentication address can be a frustrating issue. However, by checking the configuration settings, firewall settings, and ensuring the RADIUS server is listening on the correct IP address, you can resolve this issue. Always remember to check the server logs for any error messages or warnings that could provide additional clues to the issue.

For further reading on RADIUS and its configuration, you can visit the official FreeRADIUS documentation.

What is RADIUS?

RADIUS (Remote Authentication Dial-In User Service) is a client/server protocol and software that enables remote access servers to communicate with a central server to authenticate dial-in users and authorize their access to the requested system or service.

Why is RADIUS ignoring requests to the authentication address?

RADIUS may ignore requests to the authentication address due to incorrect configuration settings, firewall settings, or the RADIUS server not listening on the correct IP address.

How can I check the configuration settings in RADIUS?

You can check the configuration settings in RADIUS by reviewing the clients.conf file, which contains the definitions of RADIUS clients that are allowed to use the server. Each client IP address needs to be correctly defined with the correct shared secret.

What should I do if RADIUS is ignoring requests due to firewall settings?

If RADIUS is ignoring requests due to firewall settings, you need to allow the necessary ports (1812 for authentication and 1813 for accounting, by default) through the firewall. You can use the command sudo ufw allow [port] to open the specified port.

How can I verify if the RADIUS server is listening on the correct IP address?

To verify if the RADIUS server is listening on the correct IP address, you can check the radiusd.conf file under the listen configuration. Make sure the IP address specified is correct.

What should I do if the issue persists after checking the configuration and firewall settings?

If the issue persists, it may be helpful to examine the output of sudo freeradius -X for any error messages or warnings that could provide further insight into the problem. Additionally, checking the server logs for any error messages or warnings can also provide clues to the issue.

Where can I find further information on RADIUS and its configuration?

For further reading on RADIUS and its configuration, you can visit the official FreeRADIUS documentation at [http://wiki.freeradius.org/].

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