AirPort Extreme, Express: Using the NAT Port Mapping Protocol for faster .Mac syncing

If you're a .Mac member and have iDisk Syncing and/or .Mac data syncing enabled on two or more computers, you can speed up the synchronization process by turning on the NAT Port Mapping Protocol (NAT-PMP) on your AirPort Extreme Base Station or AirPort Express. Before we show you how to do this, make sure that you meet the following requirements:

Each computer must have Mac OS X 10.4.2 or later.
Each computer must have AirPort software 4.2 or later.
If using Airport Extreme, it must have firmware 5.6 or later.
If using Airport Express, it must have firmware 6.2 or later.
AirPort Extreme or AirPort Express must be the device that is sharing your Internet connection (it must be the NAT router).
Learn how to update Mac OS X and AirPort software.
Learn how to update AirPort Extreme or Express firmware.

Enabling the NAT Port Mapping Protocol

In the Finder, choose Utilities from the Go menu.
Open Airport Admin Utility.
In the resulting Select Base Station window, select your Airport Extreme or AirPort Express from the list.
Click Configure, then enter the base station password when prompted.
Click the Base Station Options button.
Select the Enable NAT Port Mapping Protocol checkbox.
Click OK.
Click the Update button and wait for the base station to restart.
After your Airport Extreme or AirPort Express restarts, NAT-PMP will be enabled.

About iDisk Syncing and NAT-PMP

If you enable iDisk Syncing in the .Mac pane of System Preferences, or any other .Mac-based sync service, making a change to a synchronized item on one computer will result in the same change being made to another computer on which you have the feature enabled.

NAT-PMP speeds up this process by allowing .Mac servers to initiate contact with other Macintosh systems behind your NAT router as soon as an iDisk update occurs. Otherwise, the sync will occur when another one of your computers initiates contact with the server, which might take up to an hour.