Connecting to Comcast cable internet

[milanuk]

Hello all,

Our daughter headed off to college this fall, and I sent along a wifi router mostly set up and ready to go so when she moved into her apartment, there would be minimal config left to do so that she wouldn't be tied to one jack in the bedroom or wherever. Even walked through the config process so she could finish up without needing me there (its about 3 hrs away in Spokane).

Cable guy comes, sets up everything and configures her *laptop* to connect direct via the ethernet cable to the cable modem, not the wifi router. She calls Comcast, they say essentially 'not their equipment, not their problem' as the basic connection works and thats where their level of GaS ends. She got ahold of the cable guy and he said that that was exactly what he was running (cable modem to a wifi router in his home) and it worked fine for him.

So... this weekend we went over to Spokane for some shopping, and I got to beat my head on the keyboard for an hour or so. With her laptop, it just connects via the ethernet connection to the cable modem, no username, no password, just connects and gets its info via dhcp, and away it goes. The Buffalo AirStation on the other hand... no go. I can connect to it via wireless, log into its internal web control page, but it can't connect to the cable modem (with the cable plugged into it instead of the laptop). It's not a PPPoE connection like I'm used to with fiber/dsl, so I'm a little lost here. As a last resort, I tried plugging the ethernet cable into my Macbook, and still couldn't connect. Like there wasn't anything there.

Any ideas or guesses? Does Comcast 'bond' the account to the MAC address of the NIC initially used to set up the account, allowing one and only one client computer? Or is there something less nefarious going on here? Please keep in mind I don't even have remote access to this 'puter, so answers like 'try this' aren't going to be easy to try - picture trying to walk an 18yr old girl through tech support

Thanks,

Monte

[pelligrini]

I'm not familiar with your router, but is the cable modem plugged into the WAN port of the wireless router?
It looks like there are several models that have 4 LAN ports too.

[radhak]

Some initial thoughts : I have Comcast, and my setup does not bind the MAC of the machine. My brother used to simply plug in his ethernet cable to one of the available ports on the Netgear wireless router and could easily connect.

Just to confirm, the connection is :

cable connection from wall <connected to> Comcast cable-modem <connected to > Wireless Router input port <connected to > 4 wired-connections allowed and of course all wireless ones.

[cgallery]

You did power cycle the cable modem after installing the router, right?

[vanguard]

Power cycling is the trick. For some reason the cable modems remember the MAC address of the last thing connected to it. Unplug the modem for 3 mins. Connect the buffalo while its off, then turn on the modem, let it stabilize and then turn on the router and add the computer.

[avbclark]

Frequently the service does need to authenticate each MAC. I don't know how the Comcast in Spokane works, but when I had it in Sandy Ut, I had to call and tell them I was plugging in the WiFI to the modem and ask them to re authenticate from their end. When I would change equipment it frequently took several calls to get someone who knew what I was talking about.

Fast and easy if you get the right person on the other end.

FWIW my present connectivity is the same. Every time I change anything I have to call and reauthenticate.
Good Luck
Bill

[LinuxRandal]

Originally Posted by vanguard

Power cycling is the trick. For some reason the cable modems remember the MAC address of the last thing connected to it. Unplug the modem for 3 mins. Connect the buffalo while its off, then turn on the modem, let it stabilize and then turn on the router and add the computer.

Agreed. You also may/could have an option (pretty common) that would allow your router to clone the mac address of what was connected to it (this should be the physical lan, not network as it is a different mac address).

[milanuk]

Thanks guys. I spent some time using the online chat help from Comcast and after some initial difficulty getting the problem spelled out in terms they could grasp they said I needed to power cycle the cable modem so it would 'forget' the last machine attached to it, i.e. same thing y'all said. I'll have to try walking the daughter through the process tonight when I get home. Like I said, I am used to PPPoE where I just plug into the wall, so I didn't even think of power-cycling the cable modem. The frustrating part is that the people she called (including the guy who installed everything and configured her system) couldn't give her that simple answer weeks ago.

I did try cloning the MAC address of her laptop wifi NIC in the web control page of the wifi router, but it didn't help any... which does seem strange if the router was looking for that specific computer (or network adapter)? Hopefully I don't have to do the re-authenticate rigamarole described above...

Thanks,

Monte

[LinuxRandal]

Originally Posted by LinuxRandal

Agreed. You also may/could have an option (pretty common) that would allow your router to clone the mac address of what was connected to it (this should be the physical lan, not network as it is a different mac address).

Originally Posted by milanuk

I did try cloning the MAC address of her laptop wifi NIC in the web control page of the wifi router, but it didn't help any... which does seem strange if the router was looking for that specific computer (or network adapter)? Hopefully I don't have to do the re-authenticate rigamarole described above...

Thanks,

Monte

The cable modem was hooked to the wired port (mac address 1), you cloned the wireless address (mac address 2). You need to hook the wired port to the router and clone the wired address.

[milanuk]

The ethernet went from the laptop to the cable modem. I opened up the connection properties on the laptop, and wrote down everything - ip address, gateway, subnet mask, and the MAC address of that network adapter (wired ethernet). Then I unplugged the cable from the laptop, and plugged it into the WAN port on the wifi router. Connected to the wifi router via 802.11g, opened the web control panel, and cloned the MAC address from the laptop so that *to the cable modem* it should appear as though the wifi router was using the same MAC address that it was 'looking for' (the wired ethernet port on the laptop). At no point after initial setup of the wifi router did I ever plug *anything* into the wired ethernet ports on the back of the wifi outer.