Mark- 29 Posted August 9, 2019 (edited) Hello, Never used multicast before and not having success. I must send a request to a device at 192.168.1.51 port 1500 using UDP. The device will begin multicasting data on address 224.0.0.0 port 1500. I send the request and I see the device sending the data on Wireshark. I just do not get any OnDataAvaliable calls. I set the TWSocket as: multiSocket.Proto:='udp'; multiSocket.Addr:='192.168.8.169'; //nic to bind to multiSocket.Port:=portNum; //1500 multiSocket.MultiCast:=true; multiSocket.MultiCastAddrStr:='224.0.0.0'; //this is the dst address I see in wireshark, //tried the sender ip address and got error IP_ADD_MEMBERSHIP ; multiSocket.ReuseAddr:=true; multiSocket.Listen; No error, no data. I can configure the multicast address on the device. Should the address be changed? What am I doing wrong? Thanks, Mark Edited August 9, 2019 by Mark- Share this post Link to post
Mark- 29 Posted August 9, 2019 Resolved. W10 Firewall was allowing outgoing but not incoming. Share this post Link to post