I'm not running an antivirus, but I doubt Conficker can do much of an RPC stack exploit behind a Linux powered NAT device that I call router. Of course the ports for the Windows File Sharing Service are not forwarded to the open. Therefore me not downloading or manually executing a Conficker file won't do any harm. Good, I'm safe.

How does that even work? This worming into the network? AFAIK you need an open port and data to send to the network application listening on that port that does execute some weird stuff for unexpected data streams, right? So how do all those people even get a worm on their computer, except for being stupid and opening files they don't know what they are?