Troubleshoot my network.

10 Oct 2007 8:13 PM

Control Freq

I have 4 computers in my network

Win2k Laptop 192.168.1.10
WinXP Desktop 192.168.1.20
WinXP Laptop 192.168.1.13

Linux Server 192.168.1.100

The problem is that my Win2k laptop cannot ping my WinXP desktop (and
vice versa).

All other combinations work fine.

All machines are using PCMCIA wireless network adaptors in adhoc (peer-
to-peer) mode.

All machines can get to the internet (using the Linux Server as the
gateway).

I have noticed that the two machines who cannot communicate have the
same MAC Address for the Wireless network adaptor!!!! (Is this usual?)

So, is the duplicate MAC address the problem here?

Help/advice appreciated.

11 Oct 2007 12:10 AM

Jack (MVP-Networking).

Hi
Duplicate MAC address can cause problem.
MAC address is usually assigned by the manufacturer of the card and it is
hard coded in the cards firmware.
If your computer show the the same MAC address it seems that there is some
spoofing in the Widows registry that assign soft MAC address instead of
using the actual MAC address of the card.
http://support.microsoft.com/kb/118623
Jack (MVP-Networking).

Show quote

"Control Freq" <n***@nhthomas.freeserve.co.uk> wrote in message
news:1192047200.680909.108470@k79g2000hse.googlegroups.com...
>I have 4 computers in my network
>
> Win2k Laptop 192.168.1.10
> WinXP Desktop 192.168.1.20
> WinXP Laptop 192.168.1.13
>
> Linux Server 192.168.1.100
>
> The problem is that my Win2k laptop cannot ping my WinXP desktop (and
> vice versa).
>
> All other combinations work fine.
>
> All machines are using PCMCIA wireless network adaptors in adhoc (peer-
> to-peer) mode.
>
> All machines can get to the internet (using the Linux Server as the
> gateway).
>
> I have noticed that the two machines who cannot communicate have the
> same MAC Address for the Wireless network adaptor!!!! (Is this usual?)
>
> So, is the duplicate MAC address the problem here?
>
> Help/advice appreciated.
>

11 Oct 2007 12:08 PM

Control Freq

On 11 Oct, 01:10, "Jack \(MVP-Networking\)."
<j***@discussiongroup.com> wrote:
Show quote

> Hi
> Duplicate MAC address can cause problem.
> MAC address is usually assigned by the manufacturer of the card and it is
> hard coded in the cards firmware.
> If your computer show the the same MAC address it seems that there is some
> spoofing in the Widows registry that assign soft MAC address instead of
> using the actual MAC address of the card.http://support.microsoft.com/kb/118623
> Jack (MVP-Networking).
>
> "Control Freq" <n***@nhthomas.freeserve.co.uk> wrote in message
>
> news:1192047200.680909.108470@k79g2000hse.googlegroups.com...
>
>
>
> >I have 4 computers in my network
>
> > Win2k Laptop 192.168.1.10
> > WinXP Desktop 192.168.1.20
> > WinXP Laptop 192.168.1.13
>
> > Linux Server 192.168.1.100
>
> > The problem is that my Win2k laptop cannot ping my WinXP desktop (and
> > vice versa).
>
> > All other combinations work fine.
>
> > All machines are using PCMCIA wireless network adaptors in adhoc (peer-
> > to-peer) mode.
>
> > All machines can get to the internet (using the Linux Server as the
> > gateway).
>
> > I have noticed that the two machines who cannot communicate have the
> > same MAC Address for the Wireless network adaptor!!!! (Is this usual?)
>
> > So, is the duplicate MAC address the problem here?
>
> > Help/advice appreciated.- Hide quoted text -
>
> - Show quoted text -

Well, it did turn out to be a duplicate MAC address problem after all.
I don't know how I got two wirless NIC with the same MAC Address, but,
downloading and running MACMakeUp helped me to change the MAC Address
of one of the wireless NICs and now all is working fine.

Good result.

Thanks guys.

Regards