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ovs-tcpdump

Dump traffic from an Open vSwitch port using tcpdump

ovs-tcpdump -i <port> <tcpdump options>...

ovs-tcpdump creates switch mirror ports in the ovs-vswitchd daemon and executes tcpdump to listen against those ports. When the tcpdump instance exits, it then cleans up the mirror port it created.

ovs-tcpdump will not allow multiple mirrors for the same port. It has some logic to parse the current configuration and prevent duplicate mirrors.

The -i option may not appear multiple times.

It is important to note that under Linux-based kernels, tap devices do not receive packets unless the specific tuntap device has been opened by an application. This requires CAP_NET_ADMIN privileges, so the ovs-tcpdump command must be run as a user with such permissions (this is usually a super-user).

  • -h or --help

    Prints a brief help message to the console.

  • -V or --version

    Prints version information to the console.

  • --db-sock <socket>

    The Open vSwitch database socket connection string. The default is unix:<rundir>/db.sock.

  • --dump-cmd <command>

    The command to run instead of tcpdump.

  • -i or --interface

    The interface for which a mirror port should be created, and packets should be dumped.

  • --mirror-to

    The name of the interface which should be the destination of the mirrored packets. If the specified interface does not exist, it will be created as part of the setup process. If the interface already exists, it must be a port type that can be used with the tcpdump utility. Mirror ports cannot be used for normal traffic. The default value is mi<port>.

  • --span

    If specified, mirror all ports (optional).

  • --filter <flow>

    If specified, only mirror packets that match the provided OpenFlow filter. The available fields are documented in ovs-fields(7).


ovs-appctl(8), ovs-vswitchd(8), ovs-pcap(1), ovs-fields(7), ovs-tcpundump(1), tcpdump(8), wireshark(8).

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