Collecting network packets

Network Administration Guide for Hitachi NAS Platform

Part Number

It is possible to perform a complete capture of network packets on a NAS server using the packet-capture command. This is useful when the server is experiencing protocol errors.

Once started, this command collects all header and content packets from the NAS server and stores them in a file in NAS memory. This file is named tmp and it can grow to a maximum size of 32MB or 15000 frames (whichever is reached first).

To retrieve this file, use the nail command to email it to a user. Alternatively, use the ssget command to send it to the NAS Manager for later collection. The ssget command works from an ssc connection and, therefore, is usable locally or on a server connected to an external SMU.

The file format is .pcap. To analyze the contents the following filter applications are supported:

  • tcpdump
  • tshark
  • wireshark

The packet-capture command also supports aggregations as shown in the example below:

packet-capture --start ag1
Server performance is severely degraded during packet capture. It is recommended to use port mirroring on the upstream switch instead of using the packet capture command on the NAS server.