Configuring a Device to Capture Packets Sent to the CPU
Context
When a CPU fault occurs, capture packets sent to the CPU for analysis. You can configure ACL rules to match the packets you want to capture.
Procedure
- Run system-view
The system view is displayed.
- Run capture-packet cpu [ vlan vlan-id | acl { ipv4-acl | ipv6 ipv6-acl } ] * destination { file file-name | terminal } * [ time-out time-out-value | packet-num number | packet-len length ] *
The device is configured to capture packets sent to the CPU.
- If the IP addresses of ARP packets on the control plane match the IP addresses in a basic or advanced ACL, these ARP packets can also be captured.
- Running this command will increase the CPU usage. Therefore, you are not advised to run this command if the CPU usage is higher than the specified value in a Warning message.
- The packet capture configuration is not saved in the configuration file, and becomes invalid when packet capture is complete.
- Different packet capture instances cannot be executed simultaneously. That is, a new packet capture instance can be executed only when the previous one is complete.
- The system limits the rate of captured packets. The default rate limit is 64 kbit/s. If the rate of packets exceeds the limit, some packets may be discarded.