Troubleshooting network management & monitoring

Mirroring issues

Failure to receive mirrored packets on monitoring device after port mirroring configuration

Symptom

The monitoring device fails to receive mirrored packets after port mirroring configuration.

Possible reasons

The following are the common causes of this type of issue:

·     The link between the mirroring source ports and the monitored network fails.

·     The configuration of the mirroring source ports or the monitor ports is incorrect.

Troubleshooting flow

Figure 1 shows the troubleshooting flowchart.

Figure 1 Flowchart for troubleshooting failure to receive mirrored packets on monitoring device after port mirroring configuration

Solution

1.     Identify whether the mirroring source ports can successfully send and receive packets.

Execute the display interface interface-type interface-number command on the source device. Check the received and sent packet statistics values in the Input(total) and Output(total) fields in the command output for a mirroring source port.

¡     If the statistics of the packets received or sent by the mirroring source port are 0 or unchanged, the link between the device and the monitored network might fail (for example, the related interfaces are down). Resolve this issue.

¡     If the statistics of the packets received and sent by the mirroring source port are not zero and continuously change, proceed to step 2.

2.     Identify whether the port mirroring configuration is correct.

On the source device, execute the display mirroring-group command to check port mirroring configuration and identify whether the configured mirroring source ports and monitor ports are correct. In the command output, the Mirroring port field displays the mirroring source ports, and the Monitor port field displays the monitor ports.

¡     If the configuration is correct, proceed to step 3.

¡     If the configuration is incorrect, execute the mirroring-group mirroring-port and mirroring-group monitor-port commands in system view to correctly reconfigure the mirroring source ports and monitor ports.

3.     Identify whether packets are sent out a destination port.

Execute the display interface interface-type interface-number command on the destination device. Check the Output(total) field in the command output to view the statistics of the packets sent by the port.

¡     If the statistics of packets sent out the destination port are 0 or do not change, execute the display interface interface-type interface-number command on the device. Check the Current state field in the command output to identify whether the interface is physically up.

-     If the interface is up, proceed to the following steps.

-     If the interface is down, resolve the issues that the interface is physically down.

¡     If the statistics of the packets sent by the destination port are not zero and continuously change, proceed to step 4.

4.     If the issue persists, collect the following information and contact Technical Support:

¡     Results of each step.

¡     The configuration file, log messages, and alarm messages.

Related alarm and log messages

N/A