Digital Imaging and Communications in Medicine (DICOM)
Wikipedia has a very good high level description about DICOM and the protocol specifications can be found at the DICOM Homepage. This page will focus on wireshark specific topics.
XXX - add a brief description of DICOM history
Following screenshot shows a DICOM communication containing a C-ECHO followed by C-STORE request.
The accepted or rejected presentation contexts are decoded, to quickly identify negotiation issues.
Starting with wireshark 1.1.xx, the DICOM dissector has many new features. is now fully functional. Also add info of additional Wireshark features where appropriate, like special statistics of this protocol.
Following settings are available to influence DICOM dissection its data display.
DICOM Ports: Comma separated list with TCP ports to decode. A range can also be specified. Example: 104, 3200, 50000-51000
Search on any TCP Port: When enabled, the DICOM dissector will parse all TCP packets not handled by any other dissector and look for an association request. This is disabled by default, to preserve resources for the non DICOM community. If you frequently look at DICOM traffic, enable this setting. If despite this enabled, the communication is still not recognized as a DICOM stream, add the TCP port to the list above.
Create Meta Header on Export: For exported PDUs, create a DICOM File Meta Header according to part 10. If the captured PDV does not contain a SOP Class UID and SOP Instance UID (e.g. for command PDVs), wireshark specific ones will be created. Meta headers are common now-a-days.
Create subtrees for Sequences and Items: This is a matter of personal taste. If enabled, each sequences and items are shown in a hierarchy as show next. Since IODs can span multiple PDUs, sequence items in subsequent PDUs, may appear as root object. For a few items, containing tags are summarized and shown as an item description. Deselect this option, if you prefer a flat display or e.g. when using TShark to create a text output.
Create subtrees for DICOM Tags: This is a matter of personal taste. By default it is disabled, as it does not add much information. However, when one wants to see, the detailed tag decoding, or more important, if one wants to search for very specific DICOM attributes, enable this setting.
Example capture file
XXX - Add a simple example capture file to the SampleCaptures page and link from here (see below). Keep this file short, it's also a good idea to gzip it to make it even smaller, as Wireshark can open gzipped files automatically.
A complete list of DICOM display filter fields can be found in the display filter reference
- Show only the DICOM based traffic:
You cannot directly filter DICOM protocols while capturing. However, if you know the TCP port used (see above), you can filter on that one.
- Capture only the DICOM traffic over the default port (80):
tcp port 104