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Interfaces / Diagnostics / Packet capture - describe new funcitonality. closes https://github.com/opnsense/docs/issues/428

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Although this isn't in a release yet, it will likely be in the near future so let's publish this in advance.
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Ad Schellevis 2022-09-01 11:13:58 +02:00
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source/manual/diagnostics_interfaces.rst
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@ -108,11 +108,54 @@ Packet capture
---------------------
The packet capture module can be used to deep dive into traffic passing a (or multiple) network interfaces.
It has some options you can choose from, such as the interface to listen on, protocol you interested in and
host to track.
It has some options you can choose from, which are detailed below.
==============================================================================================================================================
=========================== ==================================================================================================================
Interface List of interfaces to start a capture on. A tcpdump process is started on each selected interface
Promiscuous When set, the system will capture all traffic present on the interface in stead
of the traffic heading to the firewall.
Address Family Capture IPv4, IPv6 or both
Invert Protocol Select all but the protocol selected below
Protocol The protocol to filter on
Host Address This value is either the Source or Destination IP address or subnet in CIDR notation.
The packet capture will look for this address in either field.
Matching can be negated by preceding the value with ":code:`not`".
Multiple IP addresses or CIDR subnets may be specified as boolean expression.
If you leave this field blank, all packets on the specified interface will be captured.
Example: :code:`not 10.0.0.0/24 not and not 11.0.0.1`
Invert Port Select all but the port selected below
Port Port number to filter on (e.g. :code:`443` for standard https, :code:`22` for ssh)
Packet Length The Packet length is the number of bytes of each packet that will be captured.
Default value is 0, which will capture the entire frame regardless of its size.
Count This is the number of packets the packet capture will grab (per selected interface).
Default value is 100. Enter 0 (zero) for no count limit.
Description Description to be displayed in "jobs" tab
=========================== ==================================================================================================================
Packet capture uses `tcpdump <https://www.tcpdump.org/>`__ and runs in the background.
After a capture is performed you can either look into it using the **View capture** button in the jobs tab or download the pcap file(s) to inspect it in an external tool, such as `Wireshark <https://www.wireshark.org/>`__.
The jobs tab contains all running or executed captures, the following options are available per capture job:
.. raw:: html
<ul>
<li> <i class="fa fa-fw fa-spinner fa-pulse"></i>Shows the capture is currently active </li>
<li> <i class="fa fa-fw fa-remove"></i> Remove capture (stops capture when currently active) </li>
<li> <i class="fa fa-fw fa-stop"></i> Stop the current capture </li>
<li> <i class="fa fa-fw fa-play"></i> (Re)starts the current capture, removes previous results when executed before </li>
<li> <i class="fa fa-fw fa-cloud-download"></i> Download a zip file containing all captured pcap files and a json file with selected options </li>
<li> <i class="fa fa-fw fa-file"></i> View capture in high detail</li>
<li> <i class="fa fa-fw fa-file-text"></i> View capture in medium detail</li>
<li> <i class="fa fa-fw fa-file-o"></i> View capture in standard detail</li>
</ul>
.. Tip::
All view buttons can be used when the capture is still active, they will just show the details collected until now.
Packet capture uses `tcpdump <https://www.tcpdump.org/>`__ and runs in the background. After a capture is performed you can
either look into it using the **View capture** button or download the pcap file to inspect it in an external tool, such as `Wireshark <https://www.wireshark.org/>`__.
---------------------
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