3.3. Linux 2.6.14 and better

If you run a kernel higher than 2.6.14 (and you should!), you should set the following options:

CONFIG_NETFILTER_XT_TARGET_NFQUEUE=Y or m
CONFIG_NETFILTER_NETLINK=Y or m
CONFIG_IP_NF_CONNTRACK=m (we advise you don't set this option statically)
CONFIG_IP_NF_CONNTRACK_EVENTS=Y

Setting these options will allow you to use the NFQUEUE target, and use very simple Netfilter rules.