This window shows how often each value of one or more fields occurs in the capture, with the respective counts and percentages. Additionally, an Entropy value (Normalized Shannon) is computed. Every field type is supported except protocol items and text-only labels.
You can launch it directly from the Statistics menu, or by a right-click on a field in the packet details tree, which opens the dialog with that field already entered. The dialog is also available in Stratoshark, where it counts events instead of packets.
The dialog has the following controls:
ip.ttl,ip.src shows all of the TTLs for each IP address seen in the capture.
The table has a column for each field, followed by Count and Percent columns. Click a column header to sort by it; numeric and address fields sort by value. Percentages are relative to the number of packets that were counted, not to the sum of the counts. A packet that contains a field more than once is counted once for each value, so the percentages can add up to more than 100 %. A line below the table summarizes the result: the number of distinct values, the number of packets that contain the fields, the number of observations and the Entropy.
Right-click a row to open the context menu:
The button along the bottom copies the whole table as text, saves it in various formats, and opens an I/O Graph for the selected rows, as the context menu entry does. The number of rows one I/O Graph can show is limited; the tooltip of the button states the limit. opens this section and closes the dialog.
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A high Entropy value (between 0.9 and 1) indicates that values are rather evenly distributed, while a low value (0 - 0.5) on the contrary indicates one or more dominant values. |
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You can use this feature to regularly baseline your traffic, for example filters such as |