are all cable modems external?

Okay, Warren, I am so ready to be wowed with wisdom right now, because

NO ONE seems to be able to help me sufficiently with this problem.

Here's what I've done since the last post:

- Bought a new Motorola SB5100 and replaced the Scientific Atlanta

rental from Comcast. Hooked this up with the USB connection, called

Comcast to give info. on the new modem, connected to the internet just


- Switched the modem connection from USB to ethernet, following all of

the power off/on routines, of course. Same problem. Obviously not a

problem with the modem.

- Spent forever on the phone with Comcast. Was told that adding my new

router (Linksys Broadband Firewall Router BEFSX41) to the mix may either

eliminate the problem if it has something to do with a "black list" or

at list help eliminate possible sources of the problem.

- Hooked up new router using ethernet connection. It worked! I saw

the Comcast website with all its images for a couple minutes before I

went to the Linksys website to complete installation per their

instructions. They had a drop down where I was to select the "Obtain

an IP Automatically" option and save settings. Upon save, I lost my

connection and was not able to get it back.

- Spent forever on the phone with both Comcast and Linksys. They said

that something was wrong with my ethernet port hardware, since the

system could not pull an IP address. I kept questioning, because it

seemed to me that it pulled an IP address until I saved configuration

settings on the Linksys website. Both said that they were at the

limits of their support.

- Spent time on the phone with Shuttle. Was told that it could be a

problem with the motherboard and that it would need to be returned.

I'll wait for my friend to visit again and look at it himself before

I'm going to let go of my computer.

- Removed the internal phone modem from the Shuttle and replaced it

with the ethernet adapter card provided by Comcast. Hooked this up to

the router, and I am using this connection now to work on the web.

You can talk down to me on this - it wouldn't offend at all. I'm

really just learning and don't get it all. But it seems to me that if

I was able to get a connection, however brief, then my original

ethernet port should be in fine operating condition. It sounds like

some type of configuration setting is messed up. Now you mentioned

something about the config only liking one connection at a time, and

that starting with the USB first may have messed things up, but it

didn't mess things up for the additional ethernet adapter that I


Everyone else has given up on this. Any ideas to offer? Thanks!

Your modem has a config file that tells it how many computers can be connected to it. If you simply change cables without power-cycling the modem, and it is configured to only allow one connection, then if the

USB port was the first one connected, then that's the only one that will


Some modems, like Motorolas, will allow both the USB and Ethernet ports

to be used at once if the config file allows two or more connections.

Other modems, like RCA's, do not allow both interfaces to be used at once. So

even if you're paying for more than one IP address, you may not be able to

use both interfaces at the same time.

Some RCA modems even resist switching between the two interfaces even

after cold resets. So even if you're only connecting one device at a time,

and you're doing a full, cold reset of the modem, you'll have difficulty switching between interfaces.

There also could be a problem if the USB and the Ethernet network connections have been bridged by the OS. The Ethernet card may have

worked just fine when it was the only network interface, but once you started

using the USB interface for networking, you may have caused a problem.

Borrowing someone else's modem won't help you troubleshoot. The modem

you use needs to be provisioned for your account. If it's provisioned for

their account, and you're on the same network segment, it might work at your house. But if it's provisioned on a different network segment,

connecting it at your house won't work. It may mess-up your friend's account as


-- Warren H.

========== Disclaimer: My views reflect those of myself, and not my employer, my friends, nor (as she often tells me) my wife. Any resemblance to the views of anybody living or dead is coincidental. No animals were hurt in the writing of this response -- unless you count my dog who desperately wants to go outside now. Care for your landscape with Black and Decker cordless tools

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When you say you went to the Linksys website, what hostname/hostaddr did you use ? Were you really talking to the router (see below) ?

Are you able to talk to the router's web server ? Normally it would be something like Do you have any other devices on your ethernet to test with ?

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Linksys routers are

$Bill wrote:

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Ed Nielsen

Why did you even hook-up the USB connection if you were going to switch to Ethernet? Not only can't we rule-out the modem as the problem, it might be the problem, or have introduced another problem as well.

What you're saying here doesn't make any sense. Perhaps you misunderstood what was being said. Also, once you hit the 15 minute mark, the phone agent has a great incentive to tell you anything that'll get you off the phone.

I find it very strange that you would have seen the Comcast website. That's not consistant with anything else in this story. And by "Linksys website", do you mean

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on the Internet, or, which is a page that the router actually serves?

On your desktop, right-click on My Network Places, and choose Properties. Pull down the View menu, and make sure the dot is next to Tiles. Now look at all the icons under LAN or High-Speed Internet. Each should have three lines of text. The econd line of only one should say Connected, and that one should be the one who's third line is the name of your NIC. Right-click on any other enabled connections, and choose Disconnect. Then right-click on the icon for your NIC, and choose Repair.

Then go to Start > Run, type "cmd" (without the quotes), and click OK. Then type "ipconfig" (again without the quotes), and press Enter. Near the top of the results you'll see an IP address.

If the address is, you are connecting to the router just fine. The problem is not the computer, or between the computer and the router. So if you're getting this IP address, there is nothing wrong with your NIC or your motherboard.

If the address is 169.254.*.*, then your computer isn't communicating with the router. Before you can even worry about a Comcast or modem problem, you have to first solve this problem. It could be the computer hardware. It could be the OS. It could be the NIC. It could be the cable between the computer and router. It could be the router. But it's not beyond the router. (There could be another problem beyond the router, but we can't deal with that yet.)

If the address is, then the problem is the computer. Either the NIC isn't installed right, there is a problem with the motherboard, or you have some major OS issues.

If the address is anything else, type "ipconfig /release all". Then type "ipconfig /renew". Then type "ipconfig", and see what the IP address is then.

The IP address you're getting at this point will determin which direction to take the troubleshooting.

BTW... I hope you're using a different computer to access the Internet to post these messages. If you're still switching between USB and Ethernet connections on both the modem and your computer, that can make things much more complex. Note that the steps I've outlined above will disable any USB networking connection from your computer because that could be a source of a problem.

You may also need to uninstall any USB networking drivers on the computer. Switching back and forth can very easily create problems that appear to be hardware issues, but are simply problems with a flakey USB networking driver.

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You do you that the MAC address for the Ethernet port and the USB port on the Motorola SB5100 are different don't you! If you setup with the USB and then switch over to Ethernet, it's not going to work. Also you don't have to call Comcast to configure your new modem. You should be able to just plug it in and use your web browser to go to

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which will bring you to the new user sign up page.(You aren't able to go anywhere else!!!) Download the software, have your account # for Comcast, look at a bill you have handy. The software will ask you some questions, find the current modem that's hooked up and switch the account over to the new Modem. It's easier then dealing with Comcast. In fact when I called them when I was upgrading my modem to give them my new MAC address, they told me to do what I'm suggesting to you or anyone else for that matter.

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The modem has 3 MAC addresses: One for the Ethernet interface, one for the USB interface, and one for the WAN (coax) interface. The cable company only cares about the one that's on the WAN side, and it's the same whether you use the USB or Ethernet interface on the LAN side.

You are correct. Whether one is in an old SAS market, or in one that's been converted to Bedrock, it is better to configure things automatically from your end without calling Comcast. It eliminates the problem of the CAE mistyping the MAC address of the modem. However, if one is in a Bedrock market, and isn't using Windows or Mac OS, they have to call, as the required software only runs on those OS's. (SAS was a browser-based system, so any OS would work. So much for progress.)

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