xfinity wifi connectivity issue

Not sure if this is the right venue, but here goes: New Xfinity/Comcast install at my girlfriend's house a month ago, moving from Century Link/Driect TV due to satellite problems. Wifi works fine on her old hp windows notebook (that I just reformatted myself). In OS X SL I can see the network, so I input the correct WPA password and quickly get a "connection timeout". (I can connect via ethernet without a problem, but that would require running a really long cable to my office, two floors up.)

I boot into Windows 7 via bootcamp. Same basic story. No luck through Ubuntu either.

I can connect to the neighbors' unprotected Century Link DSL just fine (albeit slow). In fact, I almost never have problems connecting anywhere with my Mac, including Verizon FIOS at my old apartment, also with WPA encryption. I've checked all kinds of settings. All seem correct. I've tried DHCP and Manual. I've gone into her router settings, and I can't see anything weird there.

I've found a few references on the web, but they don't seem applicable or recent. Has anybody else encountered this? Is this a known Xfinity vs. Mac problem? Yes, if nobody here has an answer, I'll be calling the X folk soon.

JediMeister said:

Timeout issues, in my experience, are 95% of the time due to the gateway/access point/router. Before updating the firmware, try power cycling (unplug, wait a few minutes, reconnect) the networking hardware or check for firmware updates for the Xfinity box. Also, start out in the same room as the Xfinity box, and gradually move further away. Take note of what in the environment is in a direct line between the Mac and the gateway, there may be a source of wireless interference in between.

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Good points. The first time I tried it, I was in the same room as the router and only 8 feet away. I'll try powering off and on and looking for firmware updates, but I still think it's odd that the Windows machine and Mac get different results sitting right next to each other.

I thought I'd post an update, hoping someone else has had to solve this. These computers can connect AND GET INTERNET ACCESS to the Comcast/Xfinity modem/router combo:
HP Windows 7 PC via ethernet or wirelessly
HP Windows XP PC via via ethernet or wirelessly
iMac OSX 10.6 via wireless (have not tried ethernet)
Dell Mini 9 Linux via wireless (have not tried ethernet)

But my MBP running 10.6, 10.8 or Win7 can connect to the router, but CANNOT ACCESS THE INTERNET, even when connected via ethernet.

I have the feeling that the Comcast/Xfinity router is somehow blocking my mac address. Just a hunch.

Customer support is useless. They just tell me to restart everything. And if that doesn't work (which it never does), they want to charge me to troubleshoot it.

Fortunately, I'm able to get access by sharing the iMac's connection via firewire.

Unfortunately, I'm stuck with Comcast/Xfinity. DSL is out of the question in my location.

The iMac is on deathwatch, so I'm hoping to find a solution. Any ideas?

Bear said:

On the problem MBP, how is it set to configure IPv4? Using DHCP (which it should be) or some other method? You may have settings issues on the MPB. You could always delete the interfaces in network settings and re-add them. I guess you could try matching the settings to what is working on the iMac.

You never mentioned what brand the WiFi base is. Or is it actually marked as a Comcast something or other?

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The WiFi base is a standard issue Comcast Motorola.
I matched the settings on the iMac exactly on the MBP with both in booted into 10.6. No go. The weird thing is that I AM getting an IP for the MBP from the router, but at the router's config page it does not show up as a connected device and of course, I still have no internet.