WD My Book Live Duo as personal cloud and firewall

Hi

Ive been thinking about how to build myself a hardware firewall for the house using something like a WD My Book Live Duo Network Hard Drive - 6TB or a similar device? I have noticed they are advertising this as personal cloud storage.

I also want to use it as hardware firewall.

In the house it will serve security, outside the house it will let me at my personal files and music etc. Almost as the product describes but just not quite.

Has anyone seen this / can you recommend the firewall solution / OS to do this in the most convenient way

Thanks Z

 

The device only has one lan port.