Time Capsule AirPort can't find internet

Hi,

I had an AirPort Extreme as my WLAN router/AP to which 2 iMacs, 1 MacBook Pro, and 1 PC were connected wirelessly; and 1 iMac was connected via Ethernet. All of a sudden the other day, we couldn't connect to the internet.

I went through the restart modem and restart router process several times. Reset the modem twice from the ISP. Used the Ethernet to WLAN port to directly connect my desktop to the modem, and it is fine. I eventually took my Extreme to a genius appointment at an Apple Store, and after some diagnostics, the genius pronounced it dead.

I brought home a new Time Capsule and set it up using the same SSID and passwords, etc., etc. The Airport works fine. Time machine works on all of the Macs just fine. However, I still couldn't get on the net. Several hours of playing the restart, reset games, and talking with my local Apple guy and my ISP (Comcast), and paying $50 for Comcast Xfinity Signature Service, the Signature Service tech found a work-around.

She had me enter some public DNS server IP addresses (8.8.4.2, and 4.4.4.2) in the SystemPreferences>Network>Advanced>Advanced>DNS>DNS Servers box. I did this for all my Macs and they work.

I tried a few other public DNS servers, and they work this way also. I also tried Comcast's DNSsec servers (75.75.75.75 and 75.75.76.76), and they work. (I think I tried Comcast's DNS servers, too, but I'm not sure. Their web page says they're switching everyone to DNSsec by this fall.)

See: DNS : Default
and: Comcast's DNSSEC Information Center

I believe I set up my Time Capsule/AirPort correctly, and the tech didn't have me change any of it when we went through the Airport Utility settings. However, something must have gone wrong when I originally set it up, and I still have two problems:


1. If I have just the 10.0.1.1 address in the DNS server box on a given Mac, the router doesn't find the internet. This problem is mostly just annoying, but I would prefer that the router connect to the internet dynamically/automatically like it is supposed to do so.

2. The bigger problem is that I can't get on the net with my PC. It's running Windows XP Tablet, service pack 2 with the Broadcam Wireless Utility. I've run diagnostics. The diagnostic says the router can't connect to the internet. It automatically connects to the Airport router and the network WLAN. It pings OK through the Gateway IP address and to the (local) IP addresses of my Macs, but it fails a ping for finding the internet. (I get the same results if I try to ping using the CMD rather than the wireless utility.)

How do I fix this? Especially problem 2.

Can I fix this using Airport Utility?

Do I have to reset my Time Capsule/Airport router? Soft reset? Hard reset? Reset to factory default?

In any case, what do I need to do differently when setting it up?

If I do have to reset the Time Capsule, with the Time Machine back-ups still be on the Time Capsule hard drive?

First does your tablet have N capabilities and is it 5GHz or 2.4GHz in the wireless setting most (newer) Mac's will hunt and connect to 5GHz over 2.4 GHz so if you do
not have both radios in the TC set up for different devices this could be a problem.
Also there was a lot of fixes in SP3 just curious why you have not updated to that.

One of my PC which has XP 2 will not work with WPA2, although it worked fine with WEP and it's configured correctly for WPA2. The rest of the stuff on my network(PC, iMac, MBP, 2 iPads, 2 iPhones) worked with my new AE5 flawlessly.

The only solution I might suggest is to temporarily set up a guest account on the TC with a WEP password and see if it will connect.