Custom Plugin

nProbe exports flows according to the fields specified in the template with option -T (or the default template). The full list of information elements notively supported by nProbe can be generated with nprobe -H. This plugin adds the ability to define custom information elements and assign a value to them, that can be:

  • a literal string
  • a literal number
  • the result of a function applied to the actual flow

Custom fields can be specified using --custom-fields <fields>, where <fields> is a comma-separated list of <key>=<value> pairs. Field keys should be added to the template as usual using the -T <elements> option.

For instance, in the example below, we extend the @NTOPNG@ template with a few custom fields and export those custom flows to ntopng:

nprobe -i eth0 --custom-fields "FIELD1=field1,FIELD2=22,FIELD3=dummyFunction()" -T "@NTOPNG@ %FIELD1 %FIELD2 %FIELD3" --zmq tcp://*:5556


  • FIELD1 is defined as the literal string ‘field1’
  • FIELD2 is defined as the literal number ‘22’
  • FIELD3 is defined as the function dummyFunction()