One of the DSL-N13's big selling points is the inclusion of what ASUS have dubbed AiDisk. In short, this is an FTP server application run by the router, which allows you to connect any USB hard disk to the device and use it for file storage and sharing over both public and private networks. Users can be added and removed via the web interface to grant them access, and all of the usual sets of rights are available, meaning that users can be given combinations of read, write and delete access as required to either the public (WAN) or private (LAN) FTP folders. Guest access can also be allowed or disallowed, and the FTP server's port can be changed easily within the interface. Of course, this capability works best in tandem with dynamic DNS, meaning that you'll only ever have a single hostname to worry about to access files on the hard disk.