Configuring a Device to Capture Service Packets

Procedure

1. Run system-view

   The system view is displayed.

2. Run capture-packet { interface interface-type interface-number | acl { ipv4-acl | ipv6 ipv6-acl } } ^* [ vlan vlan-id | cvlan cvlan-id ] ^* destination { file file-name | terminal } ^* [ car cir car-value | time-out time-out-value | packet-num number | packet-len length | { inbound | outbound } ] ^*

   The device is configured to capture service packets.

   

   • Currently, packets on the management interface, logical stack ports, and stack member ports cannot be captured.
   • 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.
   • 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.
   • The device cannot capture the packets of fast ICMP reply, BFD, 802.1ag, and VBST.
   • When an S2720-EI, S5720I-SI, S5720-LI, S5735-L, S5735S-L, S5735S-L-M, S5720S-LI, S5720S-SI, S5720-SI, S5735-S, S5735S-S, S5735-S-I, S5730S-EI, S5730-SI, S6720-LI, S6720S-LI, S6720S-SI, or S6720-SI discards the packets that it cannot forward, packets may not be captured in some situations. It is recommended that you obtain packets in other ways, such as mirroring.
   • For the S2720-EI, S5720-LI, S5735-L, S5735S-L, S5735S-L-M, S5720S-LI, S5720-SI, S5735-S, S5735S-S, S5735-S-I, S5720S-SI, S5720I-SI, S5730-SI, S5730S-EI, S6720-LI, S6720S-LI, S6720-SI, and S6720S-SI, the VLAN ID in the packets captured using this command is not the original VLAN ID but the VLAN ID replaced during Layer 3 forwarding. However, the packets can be forwarded normally without affecting services.
   • In an SVF system, an Eth-Trunk bound to a fabric port does not support service packet capture.