mark ftp passive connections

["Marco Berizzi" <pupilla@xxxxxxxxxxx>]

I would like how to mark ftp passive connections with connmark.
Currently I have resolved this problem in the following manner:

# mark ftp active conn (no problem)
--protocol tcp --dports 20,21 -j MARK --set-mark 1
# mark ftp passive data conn with helper's help
-m helper --helper ftp -j MARK --set-mark 1

TIA