Hi, I'm using build 7100 on all machines involved. I have a home group setup and all of the computers I'm talking about have successfully joined the home group. I have one desktop computer at home. I have a portable which moves around. My networking is DSL -> NAT/Router/Wireless Access Point. There is a wired connection from the router to the desktop computer. The portable is connected via wireless. The desktop computer has some media files I'd like to play on the portable via streaming. I've setup an online ID and connected both computers to the online ID. Finally, the network is classified as a "Home" network in both cases. Finally, on the NAT I'm pretty sure I've punched through the ports requested (44553 _. 10245 and 443 -> 10245 from external to the desktop computer). At home, the portable has no trouble playing the files. I can browse the files, play them, etc. When I take the portable to another network (starbucks, home, etc.) and hook up to wireless (the network is classified as "Public" or "Work"), I open up windows media player - under the "Other libraries" heading I still see the computer that was listed with the ID. However, when I click on "videos->Folders" it says "contacting..." and after a while claims the connection has failed. I can also open up the "Internet Home Media Access" dialog box and click "Diagnose connections". In the top panel everything is ok except for Teredo which is "FAIL". Under the bottom pannel everyone's name resolution seems to succeed, but the "Connection" for my desktop computer is always listed as "FAIL". I have no idea how to debug this; I don't know what is important (is the Teredo the root cause of the failure, or is it, as a tunneling protocal, only needed if I'm on a IPv6 network!?). If that is the problem, what am I doing that messes that up? If that isn't the problem then all I have to go on is the "FAIL" for the connection, which doesn't tell me much about where to look. If I've messed up the NAT routing, I don't know how to test that. If the routing was setup automatically, I'm not even sure how to check to see if that happened on my router (Linksys WRT300N) - or if I need to do something like reboot W7 to get it to try to reconfig the router itself after I've removed the routing info from the tables in the router, etc. etc. I've not tried DMZ, but I suppose I could (I really would like to keep the NAT if I can). Many thanks in advance for any suggestions Gordon.