# opapacketcapture

Starts capturing packet data.

To stop capture and trigger dump, use `SIGINT` or `SIGUSR1`. Program dumps packets to file and exits.

Note: Using `opapacketcapture` with large amounts of traffic can cause performance issues on the given host. Intel recommends you use `opapacketcapture` on hosts with lower packet rates and bandwidth.

## Syntax

    opapacketcapture [-o outfile] [-d devfile] [-f filterfile] [-t triggerfile]
    [-l triggerlag][-a alarm] [-p packets] [-s maxblocks] [-v [-v]]

## Options

`--help`

  Produces full help text.

`-o outfile`

  Specifies the output file for captured packets. Default is packetDump.pcap

`-d devfile`

  Specifies the device file for capturing packets.

`-f filterfile`

  Specifies the file used for filtering. If absent, no filtering is done.

`-t triggerfile`

  Specifies the file used for triggering a stop capture. If absent, normal triggering is performed.

`-l triggerlag`

  Specifies the number of packets to collect after trigger condition is met, before dumping data and exiting. Default is 10.

`-a alarm`

  Specifies the number of seconds for alarm trigger to dump capture and exit.

`-p packets`

  Specifies the number of packets for alarm trigger to dump capture and exit.

`-s maxblocks`

  Specifies the number of blocks to allocate for ring buffer. Value is in Millions. Default is 2 which corresponds to 128 MiB because 1 block = 64 Bytes.

`-v`

  Produces verbose output. (Use verbose Level 1+ to show levels.)

## Example

    # opapacketcapture
    opapacketcapture: Capturing packets using 128 MiB buffer
    ^C
    opapacketcapture: Triggered
    Number of packets stored is 100

In the example above, `opapacketcapture` operates until CTRL+C is entered.