IPv4 masquerade support

modulename: nf_nat_masquerade_ipv4.ko

configname: CONFIG_NF_NAT_MASQUERADE_IPV4

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>Network packet filtering framework (Netfilter)
└─>IP: Netfilter Configuration
└─>IPv4 masquerade support
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This is the kernel functionality to provide NAT in the masquerade
flavour (automatic source address selection).

source code:
net/ipv4/netfilter/nf_nat_masquerade_ipv4.c