How to eliminate Port Blocked Alert

Contents

Objective

Requirements

Introduction

Make sure Loopback Detection is enabled

Identify the ports causing the loop

Conclusion

Objective

This article introduces how to eliminate Port Blocked Alert on the Omada Controller.

Requirements

Omada Controller (Software Controller / Hardware Controller / Cloud-Based Controller)
Omada Switch

When the Loopback Detection function is enabled on the switch, a Port Blocked Alert will be generated if a loop occurs. The Spanning Tree Protocol (STP) can also block corresponding ports according to the network topology to prevent loops that lead to broadcast storms.

The Port Blocked Alert will be automatically cleared once the loop is eliminated. To eliminate the loop, follow the guidance below:

Ensure Loopback Detection is enabled: When this function is enabled, the switch will block the ports causing the loop in the network topology, and a Port Blocked Alert will be generated on the Controller.
Identify the ports causing the loop: Identify the blocked ports based on the alert information, and check the network topology to eliminate the loop.

Make sure Loopback Detection is enabled

Step 1. Go to Devices, click the device to open its Properties window, and then go to Config > Services. Here you can find the Loopback Control, which is enabled by default.

The Device List page and the Properties window of selected switch, now the page of Config selected and Services module unfolded.

Step 2. Check Enable to enable the Lookback Detection function, and then click Apply to save.

Loopback Control is enabled, and the settings are applied.

Identify the ports causing the loop

Step 1. Go to Logs > Alerts. Here you can find the Port Blocked Alert showing that “XXX's port Tw X/X/X was blocked”. Check the corresponding port in the network topology to eliminate the loop, and the Port Blocked Alert will then be automatically cleared.

Logs page. Alerts module. A log of Port Blocked is shown on the list.