The K Desktop Environment

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4.3 Packet Filtering

Network packets can be filtered with a program that is passed to the underlying packet capture code. The filter program is specified on the Filter/triggers page, in the Packet Filter tab. Simple filter programs can be specified by selecting various options as described below. More complicated filters are the same as those passed on the command line to the tcpdump(8) command, and have to be entered directly.

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The Use program checkbox controls whch if the above two cases applies; to enter full tcpdump(8) filter programs, it should be checked. Note that controls in the program area are enabled and disabled as appropriate, however, the program generated in simple mode is shown in the bottom-most field (and can then be edited if Use program is checked.

As noted above, when the Set button is pressed, the filter program equivalent to the above settings appears in the bottom-most control. If the Use program box is then checked, it can be edited further; pressing Set again will then use this filter program.

The Verify button can be used to verify that the filter program is valid. Note that this applies to the displayed values; the Set button does not need to be pressed first.

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