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AR Router Troubleshooting Guide

This Product Documentation provides guidance for maintaining AR Enterprise Router, covering common information collection and fault diagnostic commands, typical fault troubleshooting guide, and troubleshooting.
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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Troubleshooting Procedure

Troubleshooting Procedure


Saving the results of each troubleshooting step is recommended. If troubleshooting fails to correct the fault, you will have a record of your actions to provide technical support personnel.


  1. Check that SYN Flood attack defense is enabled.

    Run the display firewall defend flag command to check whether SYN Flood attack defense is enabled. If the value of SYN Flood flag is Enable, SYN Flood attack defense has been enabled.

    If SYN Flood attack defense is disabled, run the firewall defend syn-flood enable command in the system view to enable it.

    If SYN Flood attack defense has been enabled, go to step 2.

  2. Check whether the packet rate threshold is too large.

    Run the display firewall defend syn-flood ip or display firewall defend syn-flood zone command to view the IP address or zone-based packet rate threshold.

    In the output information, MR(pps) indicates how many packets with the same destination IP address can pass the firewall in one second.


    The default packet rate threshold is 1000 pps.

    • To set or change the packet rate threshold, run the firewall defend syn-flood command in the system view.

    • If the packet rate threshold is set properly, go to step 3.

  3. Collect the following information and contact technical support personnel:

    • Results of the preceding troubleshooting procedure

    • Configuration files, log files, and alarm files of the switches

Updated: 2019-05-10

Document ID: EDOC1000079719

Views: 444789

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