I can get onto E-Shop, download games, and check my friends list, but for some reason when I play AC: New Leaf, it won't let me go into other towns. (Likewise for people trying to come in.) It gives me the error code: 018-0512, I've tried doing the custom ip address/subnet mask/gateway, but when I go to test when it's all done with it says 'connection failed'.

Anyone else have this problem and found a solution? I also heard it might be the DMZ, but I don't know how to mess with that. Can anyone care to explain?