I just set up an Airport Extreme to replace an existing Linksys router. I'm using PPOE to connect to the Internet. I have wired and wireless connected computers.

The wired ones are connected to a Dell PowerConnect 2708 gigabit Ethernet switch.

All is well when I connect to my wireless network but when I use a computer connected to the switch (wired), I cannot connect to the Internet. All other network functions work (I can ping other computers, I can print to network printers, etc.). I just can't connect to the Internet.

Is there something I'm missing? The switch is on the same subnet as my computers but I'm wondering about the AEBS. How do I know what IP address it is set at? I looked in Airport Utility and Network Utility and can't find it.

Edit: Forgot to mention, when I unplug my cable from the switch and into the Ethernet ports of my AEBS, I can access the Internet. Somehow, the AEBS is blocking Internet traffic from my switch.

Found out the problem after a lot of configuring and reconfiguring, running up and down to my wiring closet, checking different Macs and PCs, etc., etc.

I also talked to Applecare for close to 1 hour. Got escalated once to the next level of support and he couldn't figure it out either.

The problem is very straightforward and has to do with Apple's propensity to "Think Different".

The AEBS default IP address is 10.0.1.1. My switch IP address was manually set at 192.168.0.14. Because the two devices were in different subnets, they had difficulty communicating. It was not consistent. Sometimes it would work, other times not.

Changing the switch IP address to 10.0.1.14 fixed it.

It also fixed a problem with an Airport Disk not being recognised.