IPv4 connection tracking support (required for NAT)

modulename: nf_conntrack_ipv4.ko

configname: CONFIG_NF_CONNTRACK_IPV4

Linux Kernel Configuration
└─>Networking
└─>Networking options
└─>Network packet filtering framework (Netfilter)
└─>IP: Netfilter Configuration
└─>IPv4 connection tracking support (required for NAT)
In linux kernel since version 2.6.15 (release Date: 2006-01-02)  
Connection tracking keeps a record of what packets have passed
through your machine, in order to figure out how they are related
into connections.

This is IPv4 support on Layer 3 independent connection tracking.
Layer 3 independent connection tracking is experimental scheme
which generalize ip_conntrack to support other layer 3 protocols.

To compile it as a module, choose M here. If unsure, say N.

source code: