Troubleshooting 802.1X (Dot1X) Authentication Issues on TP-Link Omada Switches

If you're experiencing issues with devices being unable to authenticate after configuring the 802.1X feature on an Omada Switch, you can use the troubleshooting steps below to resolve the problem.

Troubleshooting Steps​​

Step 1. Verify the Dot1X authentication global configuration.

Using the GUI:

Navigate to SECURITY > 802.1X > Global Config, where you can see that the 802.1X function has been enabled.

The Omada Switch supports both EAP and PAP protocols for authentication. The main difference between the EAP and PAP protocols is the generation and transmission of the encryption key for the user's password information.

In the EAP protocol, the RADIUS server generates the random encryption key used to encrypt the user's password information. The switch is only responsible for transparently transmitting the EAP packets to the authentication server, which completes the entire authentication process. Using the EAP protocol requires the Radius server to support it.

In the PAP protocol, the device generates the random encryption key used to encrypt the user's password information. The switch sends the username, random encryption key, and encrypted password information to the Radius server for the relevant authentication processing. The existing Radius servers generally support the PAP protocol.

It can be seen that the EAP protocol places less pressure on the switch but more on the authentication server, while the PAP protocol is just the opposite. You can choose the appropriate protocol based on your network needs.

Note: If the client device does not use the TP-Link client software, the Handshake option must be disabled.

Using the Controller:

Go to Settings > Authentication > 802.1X, where you can see that the 802.1X function has been enabled and the EAP protocol has been selected.

Using the CLI: Switch# show dot1x global

Step 2. Verify the Dot 1X authentication port configuration.

Using the GUI:

Go to SECURITY > 802.1X > Port Config and check whether 802.1X is enabled on the relative port and whether Port Control is set to Auto.

For user devices that do not support 802.1X, the corresponding ports need to enable both the 802.1X and MAB functions. Most printers, IP phones, and fax machines do not support 802.1X. After enabling the MAB function, the switch will send the RADIUS access request to the Radius Server using the user device's MAC address as the username and password.

Using the Controller:

Go to Settings > Authentication > 802.1X, where you can see the switches and ports that have 802.1X enabled. The Port Control is set to Auto by default in the Controller mode.

Using the CLI: Switch#show dot1x interface

Step 3. Verify the network connectivity.

Make sure the network link between the switch and the Radius Server is normal, and also ensure that the authentication port (usually 1812, but there are exceptions) used by the Radius Server is enabled.

Step 4. Verify the RADIUS Server configuration.

Using the GUI:

Go to SECURITY > AAA > RADIUS Config and check whether the Radius Server’s IP address, Shared Key, and authentication port are configured correctly.

Using the Controller:

Go to Settings > Profiles > RADIUS Profile to check the information.

Using the CLI: Switch#show radius-server

Step 5. Verify the Server Group configuration.

Using the GUI:

Go to SECURITY > AAA > Server Group, and check if the correspondence between the Radius Server Group and the Server IP is configured correctly. By default, the radius Server Group will include the IP addresses of all RADIUS Servers.

Using the Controller: Skip this step in Controller mode.

Using the CLI: Switch#show aaa group radius

Step 6. Check the RADIUS Server Group selected for 802.1X.

Using the GUI:

Go to SECURITY > AAA > Dot 1X Config and check whether the Radius Server Group configured in the previous step is selected, which is usually the default.

Using the Controller:

Go to Settings > Authentication > 802.1X, where you can see the RADIUS Profile selected, which is the one previously seen in Step 4.

Using the CLI: Switch#show aaa authentication

Step 7. Check if ACL, IMPB, MAC Filtering, or other security policies are configured.

Step 8. Check the client software.

Ensure the client software is not damaged and the client software version supports the current authentication method.

If the above troubleshooting steps still do not solve the problem, you can try replacing the client software.