since when is google authoritative for my ISP?
the issue is that mIRC appears to use the result of a /userhost against the DCC requestor's nickname... I've had sniffers watching both clients and the uplink to the server... the /userhost is sent from the target client to the server, who answers directly (without contacting the client), presumably from cached state information -- I started sniffing after the clients had logged-in to the server so missed the identity exchanges...
as everything I can see or display from the individual clients leads me to believe that it's the IRC server that is getting the obscured address in a url that won't resolve... so just exactly how is using google supposed to help? to prove that, I shut off dhcp and manually set the ns addresses (verified with ipconfig) and got the same results...
I think I'll try using an entirely different IRC server to see if there is different behavior, and if so, ask some questions of the admins...