I recently switched to mac. I have an NAS attached to my airport extreme and I'm trying to access it remotely. Connected is a DLINK NAS DNS-323, which holds 2 SATA hard drives and has a built in FTP feature. I gather I have to open my ports to get in but can't figure out exactly how to do so. I thought I did so by getting into the airport utility port mapping, and adding the DLINK to that, but must be doing something wrong. Any ideas?