CONFIG_NF_NAT_PROTO_GRE (not configurable)
modulename: nf_nat_proto_gre.ko
configname: CONFIG_NF_NAT_PROTO_GRE
Linux Kernel Configuration
└─>Networking
└─>Networking options
└─>Network packet filtering framework (Netfilter)
└─>IP: Netfilter Configuration
└─>NF_NAT_PROTO_GRE