option name value description ipv _join_group ip _mreq join multicast group ip _mreq is packed binary string containing (multiaddrindexwhere multiaddr is -bit ipv multicast address and index is -bit unsigned integer interface index for the local interface leave multicast group hop-limit for multicast packets interface index for outgoing multicast packets deliver outgoing multicast packets back to local application set the next hop address for outgoing packets sockaddr_in is packed binary string containing the sockaddr_in structure as typically defined in packet information structure ip _pktinfo is packed binary string containing (addrindexwhere addr is -bit ipv address and index is bit unsigned integer with the interface index receive destination options receive the hop limit receive hop-by-hop options receive packet information receive routing header receive the traffic class routing header ip _rthdr is packed binary string containing (nextlentypesegleftdatawhere nextlentypeand segleft are all -bit unsigned integers and data is routing data see rfc destination options header before the routing options header enable the receipt of ipv _pathmtu ancillary data items traffic class hop limit for unicast packets path mtu discovery disables it for all desinations - disables it only for multicast destinations only connect to other ipv nodes ipv _leave_group ip _mreq ipv _multicast_hops int ipv _multicast_if int ipv _multicast_loop , ipv _nexthop sockaddr_in ipv _pktinfo ip _pktinfo ipv _recvdstopts ipv _recvhoplimit ipv _recvhopopts ipv _recvpktinfo ipv _recvrthdr ipv _recvtclass ipv _rthdr , , , , , , ip _rthdr ipv _rthdrdstopts ip _dest ipv _recvpathmtu , ipv _tclass ipv _unicast_hops ipv _use_min_mtu int int - , , ipv _v only , lib fl ff