We have done some extensive testing and research and we have determined that this problem is a fault with Windows/Winsock. Apparently, Winsock blocks all Type 8 ICMP packets, but passes all other packets through to any socket that can handle ICMP, which is why our controls can receive Type 0 ICMP echo replies, but cannot receive the Type 8 echo request. We have not been able to find any workarounds for this problem.

In short, on Windows machines, ICMPPort can only be used as a server to receive any ICMP packet that is not of Type 8.