IP: broadcast GRE over IP


Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>IP: broadcast GRE over IP
In linux kernel since version 2.6.12  
One application of GRE/IP is to construct a broadcast WAN (Wide Area
Network), which looks like a normal Ethernet LAN (Local Area
Network), but can be distributed all over the Internet. If you want
to do that, say Y here and to "IP multicast routing" below.