I discovered a FAQ for the WinXP Advanced Networking Pack Among other FAQ’s (including “What is a F.A.Q.?”) are “What is a PNRP seed server?” and “How do I know if I can contact the Microsoft hosted PNRP seed server?”. A seed server is a bootstrap for a PNRP “cloud”. PNRP is supposed to be serverless, but there has to be some way for the system to be bootstrapped. MSFT runs a seed server at a well known address (well known to the P2P system, since no one told me). To see if you can reach said seed server, you can run “netsh p2p pnrp diag ping seed”. If the number is one or greater, all is good. In my case, that command raises Error 0x800706d9: “There are no more endpoints available from the endpoint mapper”. I’m not sure what that means, but I’m guessing that explains why I can’t resolve PNRP names.