Subject: From: Date:

Re: [ECS] Cable modem / no IP address ? Ingo Pakleppa Thu, 30 Nov 2000 00:22:36 -0800

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Well, first off, this is not an ECS problem at all, so it is really his 
responsibility to get the computer working. You shouldn't have to provide 
general PC support. But apart from that:

The cable company's response is indeed very informative, even if it may not 
seem so. They are telling him that they use DHCP to assign IP addresses, 
and that the IP addresses have an lease expiration time of six days (the 
leases get renewed after half that time is up, if the PC is on).

The first thing he should do is check that he really has the Ethernet card 
selected in WINIPCFG - not "PPP Adapter" or so (WINIPCFG has a drop-down 
box, and unfortunately by default, it seems to show PPP Adapter if there is 
one installed). PPP would always show IP address 0.0.0.0 unless you are 
dialed in. One easy way to tell if the correct card is selected is by 
looking whether the Release and Renew buttons are greyed or not - they must 
be available (there also is a Release All and Renew All button - they are 
always active, so they don't tell you much).

Next, try clicking on the Release button (this is only active when an 
Ethernet card is selected). Probably, nothing will happen - it's just a 
precaution. Then click on Renew and see if he now gets an IP address. If 
so, he is all set.

If not, he should check the driver for the Ethernet card (I have seen some 
drivers that don't work unless you configure that card's MAC address, which 
you had to get from the software that came with the card, which in turn 
only runs under straight DOS. Yikes!).

Another common problem is that you usually MUST configure the DNS name of 
the computer to what the cable company specifies. By default, Windows uses 
the computer name as the DNS name, so when the cable people install a 
computer, they'll just configure it to be named "CX-12344561-A" (or 
whatever their naming scheme dictates). If you rename the computer to 
"VOODOO", then the cable company's DNS server will see a request for IP 
address from VOODOO, and reject it because it doesn't know the name.

There are two solutions to that problem: the simple one is to rename the 
computer back to what the cable company wanted you to use.

If you insist on your computer being called VOODOO, you can do that, too. 
In that case, you need to go to the DNS Configuration in the Network 
Control Panel applet, and specify the name assigned by the cable company as 
the Host name. You may also need to specify the domain name that the cable 
company gave you. Leave all other settings untouched.

Next, check the cable connection.

One catch many people aren't aware of is that Ethernet cables are not 
symmetrical - like RS232 cables, there are "straight through" cables and 
"crossover" (the Ethernet equivalent of a nullmodem cable). If he connects 
his computer to the cable modem directly, he probably must use a crossover 
cable (the cable supplied by the cable company typically is a crossover 
cable). If he has a hub between PC and cable modem, whether he needs to use 
a crossover or straight-through cable depends on which port on the hub he 
uses. Typically, crossover cables are easily identified because they 
usually have a sticker wrapped around one end. Not always, though.

This is a pretty complex issue, but in short: if he did not use the cable 
that came with the cable modem, chances are that that is the cause of his 
problems. Of course, the cable itself could also be bad.

If all that doesn't help, maybe the cable company uses some schemes such as 
PPoP or something crazy like that.

Ingo

At 08:45 AM 11/29/2000 -0500, Mark Gilmore wrote:
>Hi all,
>An ECS evaluator has a cable modem (3M CMX), which apparently
>required the installation of an ETHERNET card (to support it).
>The problem is that his PC shows NO IP address (i.e. WINIPCFG
>reports "0.0.0.0"), and hence he cannot use the WWW interface.
>
>He spoke to his cable company about this, and they gave this
>"informative" response:
>    "The IP address that are assigned to all cable subscribes are
>    "Dynamic IP address" approx. every 72 hours is updated, providing
>    the PC is on continuously or every time you go on line.".
>
>Any clues on this one ?
>THANKS,
>--
>Mark Gilmore
>Omnipotence (ECS home automation software)
>http://omnipotencesoftware.com
>423-745-0026
>Hours: Mon-Sat, 9AM-8PM/EST

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