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DHCP Reservations and and changing MAC Addresses each time I reboot

dougshepard
dougshepard asked
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Last Modified: 2010-04-18
I use NAT in my firewall to remote desktop into my work computer from home (or anywhere).  My old work computer was set to use DHCP, but as long as I logged in at least every 90 days, it kept the same IP address so it always worked fine.  My new computer has an NVIDEA nForce Networking Controller (it's an HP AMD Opteron Dual Core).  I noticed that my IP address kept changing when I rebooted, so I made a DHCP Reservation for it.  That didn't work either.  That's when I realized that every time I reboot my MAC address changes (back and forth between two different ones).  It actually reverses the 2-digit combinations (e.g. 12-34-56-78-9A becomes 9A-78-56-34-12).  I am getting the MAC address by going to DOS and typing IPCONFIG -ALL.  

Any idea why the MAC address would change each reboot?  I only have one controller (and certainly only one network cable attached).

Thanks

Doug
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Top Expert 2005

Commented:
It's reversing it...too weird.

Let me see what I can find.

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Top Expert 2005

Commented:
Is IPV6 installed on your box by chance?  If so, uninstall it or disable the service (net stop tcpip6) and set it to disabled.

Author

Commented:
On my new computer or on my DHCP server?

Thanks

Doug

Author

Commented:
Either way, it's not installed on either one.

Thanks

Doug
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Top Expert 2006

Commented:
is this happening with every address or is it an intermittent problem - that is kinda messed up!
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Top Expert 2005

Commented:
Does this reversal happen inside the LAN also or only when remoting in?

Author

Commented:
The IP address is assigned at boot-up, so it's happening regardless of remoting in.

It's happening only on this computer / network card / MAC address(es).

Thanks

Doug
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Top Expert 2006

Commented:
im stumped, never seen anything like it before! hopefully someone can give you some more insight into it

cheers mate
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Top Expert 2005
Commented:
I've never experienced anything like this either....I wouldn't even know what to start looking at even if I had access to it...

You might have to disable the onboard NIC and install a PCI NIC to see if it's just simply a bad NIC chip.

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Top Expert 2006

Commented:
sounds like your NIC may have drug issues :)

Author

Commented:
I had HP send out a new motherboard (integrated NIC) and that fixed the problem (no more changing MAC address).  You might want to keep this question since I did find a solution.  Refund or not, I don't mind either way.  Sorry for the delay in posting this solution.

Thanks

Doug

Commented:
Hello Doug,

Thanks for your quick response. Since you did find the solution, and the NIC's behavior was quite weird (never saw that myself), I consider the question complete and worth keeping.

In that case, I would suggest that Netman's last comment was the best lead to the solution, and recommend to grant him the points.

Cheers

vsg375
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