asked on

DHCP Reservations and and changing MAC Addresses each time I reboot

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

Netman66

It's reversing it...too weird.

Let me see what I can find.

Netman66

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

dougshepard

ASKER

On my new computer or on my DHCP server?

Thanks

Doug

dougshepard

ASKER

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

Thanks

Doug

Jay_Jay70

is this happening with every address or is it an intermittent problem - that is kinda messed up!

Netman66

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

dougshepard

ASKER

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

Jay_Jay70

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

cheers mate

ASKER CERTIFIED SOLUTION

Netman66

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Jay_Jay70

sounds like your NIC may have drug issues :)

dougshepard

ASKER

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

vsg375

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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