Mark-

Thank you, I will look into it.

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

Resolved. W10 Firewall was allowing outgoing but not incoming.

Hello, Can the ICS logger log all data sent/received? All "LogOptions" enabled, no data bytes. TIcsLoggerVersion = 840; Thanks, Mark

Thanks for the reply. It actually was a logic mistake in the OnDataAvailable event handler In the event I only read the data to a buffer, check a few things and then possibly post a message for handling, then exit. The issue was a message was posted when it should not have been. I have to thank W10 Pro 32 bit for exposing the issue. Why the three other test operating systems did not expose the issue,.. not sure. The code had been running for years. Perhaps the mistake surfaced because the OS and program were running in a VM.

Thanks for the answer. That was the conclusion I came to looking around in code. I am using TWSocket and I have created a bunch of generic logging code before so I will copy/paste/modify to get some data logging with DoDebugLog. The logging is only temporary. The problem. Using Wireshark the data from/to the sending and receiving computers match. The program works on W7 32 bit and 64 bit. The program works on W10 64 bit. The program has what appears to be data stream corruption issues on W10 32 bit. The data in Wireshark is correct. No development tools on W10 32 bit so I thought logging the stream from TWSocket.DataAvaliable would at least tell me the problem was before or after this event. All binary data and I am not using NativeInt. The packet size is < 200 bytes. Mark