a bit more experimentation has yielded the following:
1. both DCC CHAT and DCC SEND usually (*BUT NOT ALWAYS!*) semd the target client the true IP address of the requestor. When the requestor's true IP address is not sent, the IP address provided seems to always be the IP address of the SERVER.
***CAN ANYONE EXPLAIN WHY SOMETIMES THE SERVER ADDRESS IS SUBSTITUTED FOR THE REQUESTING CLIENT ADDRESS???
2. even when the DCC requests contain the true IP address of the requestor, the DCC accept dialogue box shows what I believe is the results of a /userhost lookup on the requesting nickname -- which in the case of my ISP the response is an encoded version of the IP address which always fails when doing a DNS lookup, resulting in no reply to the requestor.
***DOES ANYONE HAVE A SUGGESTION FOR CIRCUMVENTING THIS ANOMALY???