DHCP failed

Jaynesh · 23-03-2006, 19:23

I just got 1mb broadband, it is connected to my modem.

I connected and installed everything on my laptop and it was working great.
So i decided to install it on my other computer but i get an error during installation about DHCP failed and when the ethernet is in, it says Limited or No connectivity.

I tried netsh winsock reset catalog in command prompt.
i tried switching my cable modem of and computer off and then switching on my cable modem and then my computer.

nothing worked, i dont know whats wrong with it.
it is working on my laptop.

MovedGoalPosts · 23-03-2006, 19:28

to Cable Forum

You can only have one device (computer or router ) directly attached to the modem at any one time - all other wires must be disconnected.

You must power off and on the modem if you change the computer or router connected.

---------- Post added at 19:28 ---------- Previous post was at 19:27 ----------

If you do want to be able to use two different computers easily swithcing between both then a router is the simplest option. See the networking thread areas for advice on that.

Jaynesh · 23-03-2006, 19:33

Ive got one ethernet wire directly connecting to my modem thats it.
still wont work though.

i even tried setting it up without the cd. but i get limited or no connectivity.

MovedGoalPosts · 23-03-2006, 19:37

hmm, are you using the same cable for both laptops - so that you know it's not a cable fault.

It shouldn't be necessary to use the ntl CD if you are using ethernet. Checke the network connection itself. Are you able to uninstall all drivers, reboot the computer and reinstall?

Jaynesh · 23-03-2006, 19:42

I first installed the broadband using the cd on my laptop and it worked fine.
I then decided to install it on my computer but in the middle of the installation, it says something about DHCP failing, i tried setting it up without the cd and it said Limited or No connectivity. I restored the computer to its factory settings but still the same problem.

Is this a MAC address problem?

Chris W · 23-03-2006, 19:54

you have definately powered down the modem after disconnected the laptop, then powered up the modem and gone through the installation on the pc?

Jaynesh · 24-03-2006, 08:36

yes

mastic · 24-03-2006, 09:26

I had this and India couldn't solve it.

There appears to be a bug in XP where it doesn't assign a MAC address to on-board ethernet cards (those built into the mother board).

What you need to do is assign the card a MAC address so the DHCP server can assign you an address.

Go into control panel - select "Network Connections"

Right click on your lan adaper and select properties.

Click the configure button.

Select the Advanced tab

Look for Network Address and select that for editing.

Now there are two ways to do this. The way I used was to reboot and go into my BIOS and write down the MAC address from there, but not all BIOSes support this.

The second way is to either copy the address off another device (like the USB adapters NTL send out - it's on the label) or use something like http://students.washington.edu/natetrue/macshift/ .

Hope this helps, it solved the problem for me. NTL/India could not get their heads round this when I tried to explain it to them.

If you need any help email me

dgrout 'at' link dot co dot uk

Cheers
D

EDIT: I found a better guide for changing MAC addresses:http://www.nthelp.com/NT6/change_mac_w2k.htm

Stuart · 24-03-2006, 09:32

Quote:

Originally Posted by mastic

There appears to be a bug in XP where it doesn't assign a MAC address to on-board ethernet cards (those built into the mother board).

What you need to do is assign the card a MAC address so the DHCP server can assign you an address.

I realise this is picky, but XP does not (by default) assign Mac addresses to anything. No OS does. The Mac address is assigned by the manufacturer of the network card or chipset and is burned in the ROM.

XP does give you the chance to change it though.

mastic · 24-03-2006, 09:37

What I meant was it wasn't using the default value on the card. It was setting it to "not present" and when I changed it to the value displayed in my bios it worked.

Cheers
D

edit: this also happens on both of my pcs when i re-install windows and use the onboard LAN adapter - but doesn't happen if I use Linux.