Q: Why is Macbook Pro (and only Macbook Pro) crashing DSL modem?

Hello all,

With the caveat that I am no expert in network setups and all that stuff, I have a puzzling situation:

I have a Westell 327W gateway (DSL modem and router all-in-one) through which all my home gadgets connected to the internet. As a temporary step (I'm getting rid of DSL at some point I hope), I purchased a Cisco E1200 wireless router which I'm now using instead of the Westell's wireless router. The E1200 still has to connect to the Westell in its capacity as a DSL modem, however. The Westell's address remains 192.168.1.1 while the E1200 is 192.168.0.1. I have turned off the WiFi radio on the Westell, my home network is now using the E1200 router - again, connected to the internet via the Westell DSL modem.

Here's the problem: All my gadgets work flawlessly: My iMac, 3 iPhones, Apple TV, etc. The only problem is when I first wake up the Macbook Pro: It will connect to the internet for a minute or two but then it crashes the Westell modem. Only when I wake up the Macbook Pro will I consistantly expect the modem, within a couple of minutes, to lose sync with AT&T. The modem has to re-sync, and once it does so, the MacBook Pro works fine.

If I stay on the Macbook Pro for a long while (about an hour or two uninterrupted), the problem repeats; there is a loss of sync followed by a short wait until the modem resets itself and reconnects. The problem will also happen reliably every time I wake up the Macbook Pro.

Again, no other device shows this problem. If I don't use the Macbook, the Westell is perfectly happy.

Any suggestions on what settings I can tweek / preference files I can delete would be appreciated. The only thing I tried is flushing the DNS using a Terminal command. Didn't help.

Thanks much!