Wednesday, 7 April 2004

Tech

D-Link DSL-300G+ and Apple AirPort

Who'd have thought it? A month ago I was cursing my ADSL modem, on the verge of replacing it for one that actually worked. Instead, I've bought an identical one to install for Mum. Am I really that cruel?

No, I just figured out how to make it work. (And someone at work was flogging one on the cheap.)

The rest of this is just techie detail for anyone similarly struggling. Non-techies, look away now.

The D-Link DSL-300G+ is a good product if you want to connect just one machine to the Internet, but if you try to plug it into an Apple AirPort Base Station you'll be tearing your hair out in no time.

The problem seems to be that while the AirPort Base Station correctly obtains an IP address from the ADSL modem, it doesn't pick up a default route and so doesn't know what to do with IP packets coming in from the wireless clients.

Here's the fix.

In the UK most ADSL modems are set up to talk PPPoA. It turns out that BT now supports PPPoE on its ADSL lines, and that's something the AirPort Base Station can talk too; we just need a device to convert the ATM signal on your ADSL line into Ethernet: an RFC 1483 bridge. The DSL-300G+ can work in such a mode.

  1. Unplug everything.
  2. Plug the DSL-300G+ into the mains and the ethernet on your laptop.
  3. Go to http://192.168.0.1/ (the DSL-300G+) and reconfigure it to act as an RFC 1483 bridge.
  4. Pull the ethernet cable from your laptop and plug it into the WAN port on the AirPort Base Station (so the ADSL modem and AirPort are directly connected). Plug the AirPort Base Station into the mains.
  5. Start up AirPort Admin Utility, and configure the base station to connect to the Internet via PPPoE (username and password as supplied by your ADSL provider). Configure it to share its Internet connection using DHCP and NAT.

And you're away! I hope that helps anyone struggling with the same problem.

Posted by pab at 12:31