The module “discover_netsdr” in “rfspace_source_c.cc” failed everywhere that I tried it, except for MacOS 10.6. Here is a drop in replacement that was tested and found to work on 10.6, 10.11, 10.12, 10.13 and ubuntu 16.04 LTS. #include <net/if.h> #include <ifaddrs.h> class interfaceInformation{ public: std::string name; std::string address; std::string broadcast; }; std::vector<interfaceInformation> interfaceList(); static std::vector < unit_t > discover_netsdr() { std::vector < unit_t > units; std::vector<interfaceInformation> list=interfaceList(); for(int pass=0;pass<2;++pass){ for(size_t n=0;n<list.size();++n){ if(pass == 1){ list[n].broadcast="255.255.255.255"; } //std::cout << "name " << list[n].name << std::endl; //std::cout << "address " << list[n].address << std::endl; //std::cout << "broadcast " << list[n].broadcast << std::endl; int sockTx; int sockRx; if ( (sockTx = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) continue; if ( (sockRx = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ){ close(sockTx); continue; } int sockoptval = 1; setsockopt(sockTx, SOL_SOCKET, SO_REUSEADDR, &sockoptval, sizeof(int)); sockoptval = 1; setsockopt(sockTx, SOL_SOCKET, SO_BROADCAST, &sockoptval, sizeof(int)); struct sockaddr_in host_sa; /* local address */ struct sockaddr_in peer_sa; /* remote address */ struct sockaddr_in peer_sa2; /* remote address */ /* fill in the server's address and data */ memset((char*)&peer_sa, 0, sizeof(peer_sa)); peer_sa.sin_family = AF_INET; peer_sa.sin_addr.s_addr = htonl(inet_network(list[n].address.c_str())); peer_sa.sin_port = htons(DISCOVER_SERVER_PORT); /* fill in the server's address and data */ memset((char*)&peer_sa2, 0, sizeof(peer_sa2)); peer_sa2.sin_family = AF_INET; peer_sa2.sin_addr.s_addr = htonl(inet_network(list[n].broadcast.c_str())); peer_sa2.sin_port = htons(DISCOVER_SERVER_PORT); /* fill in the hosts's address and data */ memset(&host_sa, 0, sizeof(host_sa)); host_sa.sin_family = AF_INET; host_sa.sin_addr.s_addr = htonl(INADDR_ANY); host_sa.sin_port = htons(DISCOVER_CLIENT_PORT); if ( bind(sockTx, (struct sockaddr *)&peer_sa, sizeof(peer_sa)) < 0 ) { close(sockTx); close(sockRx); continue; } if ( bind(sockRx, (struct sockaddr *)&host_sa, sizeof(host_sa)) < 0 ) { perror("binding datagram sock2"); printf("errno %d DISCOVER_SERVER_PORT %d\n",errno,DISCOVER_SERVER_PORT); close(sockTx); close(sockRx); continue; } struct timeval tv; tv.tv_sec = 0; tv.tv_usec = 100000; if ( setsockopt(sockRx, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0 ) { close(sockRx); close(sockTx); continue; } discover_common_msg_t tx_msg; memset( (void *)&tx_msg, 0, sizeof(discover_common_msg_t) ); tx_msg.length[0] = sizeof(discover_common_msg_t); tx_msg.length[1] = sizeof(discover_common_msg_t) >> 8; tx_msg.key[0] = KEY0; tx_msg.key[1] = KEY1; tx_msg.op = MSG_REQ; sendto(sockTx, &tx_msg, sizeof(tx_msg), 0, (struct sockaddr *)&peer_sa, sizeof(peer_sa)); sendto(sockTx, &tx_msg, sizeof(tx_msg), 0, (struct sockaddr *)&peer_sa2, sizeof(peer_sa2)); while ( 1 ) { size_t rx_bytes = 0; unsigned char data[1024*2]; socklen_t addrlen = sizeof(host_sa); /* length of addresses */ int nbytes = recvfrom(sockRx, data, sizeof(data), 0, (struct sockaddr *)&host_sa, &addrlen); if ( nbytes <= 0 ) break; rx_bytes = nbytes; if ( rx_bytes >= sizeof(discover_common_msg_t) ) { discover_common_msg_t *rx_msg = (discover_common_msg_t *)data; if ( KEY0 == rx_msg->key[0] && KEY1 == rx_msg->key[1] && MSG_RESP == rx_msg->op ) { void *temp = rx_msg->port; uint16_t port = *((uint16_t *)temp); std::stringstream buffer; buffer << int(rx_msg->ipaddr[3]) << "." << int(rx_msg->ipaddr[2]) << "." << int(rx_msg->ipaddr[1]) << "." << int(rx_msg->ipaddr[0]); std::string addr=buffer.str(); //std::cout << "addr " << addr << std::endl; unit_t unit; unit.name = rx_msg->name; unit.sn = rx_msg->sn; unit.addr = addr; unit.port = port; units.push_back( unit ); } } } close(sockTx); close(sockRx); } } return units; } std::vector<interfaceInformation> interfaceList() { std::vector<interfaceInformation> list; interfaceInformation c1; struct ifaddrs *addrs,*iloop; char buf[64],buf2[64]; struct sockaddr_in *s4; getifaddrs(&addrs); for (iloop = addrs; iloop != NULL; iloop = iloop->ifa_next) { s4 = (struct sockaddr_in *)(iloop->ifa_addr); buf[0]=0; if(s4){ inet_ntop(iloop->ifa_addr->sa_family, (void *)&(s4->sin_addr), buf, sizeof(buf)); }else{ continue; } s4 = (struct sockaddr_in *)(iloop->ifa_dstaddr); buf2[0]=0; if(s4){ inet_ntop(iloop->ifa_dstaddr->sa_family, (void *)&(s4->sin_addr), buf2, sizeof(buf2)); }else{ continue; } if(!(iloop->ifa_flags & IFF_UP) || !(iloop->ifa_flags & IFF_BROADCAST))continue; c1.name = iloop->ifa_name; c1.address = buf; c1.broadcast = buf2; list.push_back(c1); } freeifaddrs(addrs); return list; }