Hi, I'm having an issue with a ping class that uses IcmpSendEcho. If I try to ping two or more IPs one after the other, it works fine. However, if I try to ping two or more at once (in separate threads), I get strange results. I traced it to the fact that the reply IP isn't the one I originally pinged in the case of simultaneous pinging. In fact, sometimes it's my own IP. However, pinging one after the other, the reply IP is always the IP I pinged (assuming the person is pingable with ICMP). Any ideas what could cause this?