Apple has released AirPort 4.0.8 Firmware Update for the AirPort Snow (dual Ethernet) Base Station. It’s not necessary for the Graphite base station or the AirPort Extreme Base Station.
AirPort 4.0.8 Firmware Update fixes an incompatibility with some customers that are unable to maintain an Internet connection using BellSouth via a DSL and/or Dial-up connection. It also provides base station support for DSL users with the Telia ISP in Sweden and expands the number of Access Control List entries. The latter is dependent on the size of the description used for each entry. The total amount of space available to import is 4K, or approximately 300 entries with just MAC addresses and no descriptions. (Apple recommends that you export your current ACL list before updating to the 4.0.8 Firmware). The update also expands the number of port mapping entries to from 10 to 20.
To use AirPort 4.0.8 Firmware Update you’ll need Mac OS X (10.1.5 or greater) plus the Networking Update and Mac OS 9.2.1 or higher. The firmware update is recommended for AirPort Software 2.1.1 or greater.