I have an at&t Motorola 2210 DSL modem. I have it configured with PPPOE protocol. It's connected to an Airport Extreme router. Everything is working fine, I can get to the internet. Wireless is working with no issues. But my reason for this post is that I want to use the Back-To-My-Mac feature in MobileMe. It is not active as it needs to have the NAT enabled. I heard that the way to do it is to configure the modem as bridge and then setup the Extreme with NAT enabled. I tried to do this but the Extreme had an issue with beginning and ending addresses. I would like to know if anyone can tell me what I can do starting with configuring the modem, to getting the Airport to work properly. Thanks in advance.
You should be able to enter the IP address for the modem...192.168.1.254....in your browser address bar and pull up the configuration pages. You may be asked for the modem access code, which is on the bottom of the device.
Click the Advanced tab on the left and look for a tab with PPP Location
You want to select Bridged Mode (PPPoE not uses) and click Save Changes
The modem will restart. +Important note....in bridge mode, you will not be able to access the configuration pages for the modem by entering the IP address in the browser bar. If you need to get back to the configuration pages again on the modem in the future, you must hold in the reset button on the modem about 10 seconds. This will reset it and you can hook it up directly to your computer and enter in the IP address of the device in your browser+
You should be able to reconfigure the AirPort Extreme without resetting it back to defaults. If you get the IP conflict messages though, you must reset the AirPort Extreme by holding in the reset button until the amber light blinks rapidly.
Connect an ethernet cable from your computer to one of the LAN ports on the AirPort Extreme.
Open AirPort Utility, click Manual Setup
Click the Internet icon
Connect Using = PPPoE
Enter your user name
Enter your password
Leave the Service Name area completely blank. Do not enter anything in this box.
Click Update to save changes
Restart your modem, you should have a green light on the AirPort Extreme in about 20 seconds
No more NAT problems this way, but you may notice that the internet connection disconnects a bit more often with PPPoE.
I haven't used Back to My Mac, so can't verify that for you.
I can verify that the setup that I provided will eliminate the double NAT on your network.
NAT is already enabled on your AirPort Extreme and the Motorola modem also furnishes NAT service. That's why you have a "double NAT"
You might want to verify that you have "double NAT" on your network although I am 99% sure that you do.
Open Macintosh HD > Applications > Utilities > Network Utility
Click the Traceroute tab
Enter a network address like "www.mac.com" (without the quotation marks)
Click Trace
Let it run until you see approximately 10-12 lines of information and then click Stop
Look at Line 2 only
If you see either a 192.168.x.x or 10.x.x.x address, you have a double NAT
When you reconfigure the modem as a bridge, the PPPoE service must be provided by the AirPort Extreme. Since the Airport Extreme has NAT enabled (and there is none on the modem), your NAT issue is solved.
I am understanding the method to the madness now. You put everything in real easy terms and I thank you for it. I tried to configure the Extreme, while first setting up the DSL Modem as bridge. The AE would not let me continue as it said there was a conflict with beginning and ending IP addresses. I am sure there is a real dumb thing I am doing ?
+The AE would not let me continue as it said there was a conflict with beginning and ending IP addresses.+
From my previous post:
"You should be able to reconfigure the AirPort Extreme without resetting it back to defaults. If you get the IP conflict messages though, you must reset the AirPort Extreme by holding in the reset button until the amber light blinks rapidly."
Did you reset the AirPort Extreme by holding in the reset button until the ambler light blinks rapidly?
If you did this, the AirPort Extreme would have needed to be reconfigured since the old settings would have been erased on the device.
Do you need help with the reset procedure or the reconfiguration of the AirPort Extreme?
Thanks again for your reply, I had to set the Modem as Bridge and then had to change the IP in the AE to 10.0... After it reset, I was able to get the Back to My Mac to enable fine. No more double NAT, etc.
