CONFIG_IP_NF_TARGET_LOG
CONFIG_IP_NF_DROPTABLE
Packet `drop' table

  The `drop; table is traversed by `interesting' packets which
  are going to be dropped.  This is mainly useful for logging packet
  drops.  See the man page for iptables(8).

  If you want to compile it as a module, say M here and read
  Documentation/modules.txt.  If unsure, say `N'.