The 'display' option forces Cisco NX-OS to display the packets while it saves the capture data to a file. When the capture data is saved to a file, the captured packets are, by default, not displayed in the terminal window. An example of a 'write' option with 'capture-filter' and an output file name of 'first-capture' is: The capture file size is limited to 10 MB.Īn example Ethanalyzer command with a 'write' option is ethanalyzer local interface inband write bootflash: capture_file_name. The 'write' option lets you write the capture data to a file in one of the storage devices (such as boothflash or logflash) on the Cisco Nexus 7000 Series Switch for later analysis. With the 'display-filter' option, Ethanalyzer first captures five packets then displays only the packets that match the filter 'ip.addr=10.10.10.2.' With the 'capture-filter' option, Ethanalyzer shows you five packets which match the filter 'host 10.10.10.2'. In this example, 'limit-captured-frames' is set to 5. However, the tmp file can fill quickly, since it first captures all packets and then displays only the desired packets. A display filter uses fully dissected packets, so you can do very complex and advanced filtering when you analyze a network tracefile. Use the 'display-filter' option in order to change the view of a capture file (tmp file). Because full dissection has not been done on the packets, the filter fields are predefined and limited. A capture filter maintains a high rate of capture while it filters. Use the 'capture-filter' option in order to select which packets to display or save to disk during capture. ^C can be used to abort and get the switch prompt back in the middle of a capture if required. Use the 'detail' option for detailed protocol information. This is a summary view of output from the ethanalyzer local interface inband command. Capture data plane traffic that is forwarded in hardware.However, Ethanalyzer can help you determine the cause of the problem. Warn you when your network experiences problems.Decode the internal 7000 header of the control packet.Filter packets to be displayed on many criteria.Filter packets captured on many criteria.Display packets with summary or detailed protocol information.Set the length of the packets to be captured.Set the number of packets to be captured.Capture packets sent or received by the Supervisor. Cisco NX-OS runs on top of the Linux kernel, which uses the libpcap library in order to support packet capture. It decodes packets captured by libpcap, the packet capture library. Wireshark is an open-source, network protocol analyzer widely used across many industries and educational institutions. This document describes the Ethanalyzer, a Cisco NX-OS integrated packet capture tool for control packets based upon Wireshark.
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