W5100S UDP Sendto zero ip address

Question

When a do a sendTo van give a valid destination ip and port, wire shark is reporting that I am sending an ip of 0.0.0.0 with port 0. I’ve created the socket with: returncode = socket(UDP_SOCK_ENC, Sn_MR_UDP, UDP_PORT_ENCAP, SF_MULTI_ENABLE); I write to the socket with: ret = sendto(sn, dataPointer + sentsize, len - sentsize,desAddr.bytes,destport); where destAddr.bytes is 192.168.1.4 and port is 4515. However, wireshark is rseporting ip of zero.

lawrence · Answer

Hi @erg144 I could not know exacty the value of your code with returncode = socket(UDP_SOCK_ENC, Sn_MR_UDP, UDP_PORT_ENCAP, SF_MULTI_ENABLE); If you want to handle UDP socket as multicast, you need to setup Sn_DHAR as multicat mac address. please check the below flows: // Multicast init setSn_DHAR(socket_num, mac addr); setSn_DIPR(socket_num, multicast addr); setSn_DPORT(socket_num, multicast_port); socket(socket_num, Sn_MR_UDP, sock_port, enable_multicast); sendto(socket_num, buf, len, multicast_addr, multicast_port); Thank you,