MAC Address Change?

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Alien
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MAC Address Change?

Post by Alien »

I apologize in advance if this should have been posted in the General Cable/DSL Forum.

My ISP is not allowing my router to connect for some reason. They have never been told that I have a router, yet I can't pull an IP. After researching, I can "clone" the MAC of my PC, and then it will pull an IP just fine from my ISP -- then my internet is back in bussiness (otherwise, it's down and an IP is not given ... of course).

If for some reason they block the MAC address for my PC that I'm cloning, I'll have to find a way around it. So, here are my questions:

Is there a way to change the MAC of my router?
Is there a way to change the MAC of my PC?
Why do cable/dsl companies record MAC addresses, and block/allow them like this?
What "spawns" the necessity for cable/dsl companies to do such a thing?

I'm sure there are other questions that I should be asking, but I'm really tired, and can't think straight LOL. :) If you can provide any further information beyond what's been asked, please do so.

If you're wondering, my ISP is Cox.net, and my router is a D-Link DI-713P rev 2.57 build 3a1 (aka: latest firmware version). My NIC is a 3Com 3C920 (laptop integrated).

Thanks for all your help!

[ A L i E N ]
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hoov
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Post by hoov »

Through the router settings you most definitely can clone a mac address to match that of your pc. Not sure where to do it in the D-Link but with a Netgear it is pretty straightforward.

Trying to change the mac of your pc nic is not always possible. From what I can remember it is only possible with a few nic cards.
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Old Fart
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Post by Old Fart »

Why do cable/dsl companies record MAC addresses, and block/allow them like this?

The recording/blocking of MAC addresses is used to control DHCP leases and prevent theft of services.

On aDSL circuits, IPs can be assigned all dynamic (always liable to change) a mix of dynamic with reservations (some change some don't , and a MAC address is required to set the reservation.) or all reserved (prevents unathorized access to your services)

Regardless of how you are set, the ISP can always look at their DHCP table and see your MAC address. After all, they have a right to control access to their system.

You are on a cable company, and the way they operate is by dynnamic addressing, but with an access list comprised of authorized MAC addresses. Basically they use your MAC address as the key to come in, If they see a MAC outside their list attempt to connect, it is not given an IP address, thereby preventing signals from it being routed.

That is why cloning the MAC they have on record works. The Linksys series will also allow you to clone MAC addresses.
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Alien
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More!

Post by Alien »

Well DLink said I can't change the MAC of the router - do you all know of any way to change the MAC of a 3com NIC?

Thanks!
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hoov
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Post by hoov »

I went to the Dlink site and looked up the manual for the d713. On page 18 in the manual it shows you where to clone the mac address.
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Old Fart
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Post by Old Fart »

Changing the MAC of your network card?

Besides probably not being possible, why would you want to do this? If you were to successfully change it, and hook directly to your cable modem, bye bye connection, as the "spoofed" MAC you enter will not be listed as having access to their system either.
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Alien
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...More...

Post by Alien »

If for some reason my router were to lose the existing MAC address that I'm cloning (the router doesn't have user-inputtable MAC addresses to clone, it only lets you select from previously connected machine's MACs) and I've upgraded my NIC, I'd have to change the MAC on the upgraded NIC for my router to use.

Why is this such an issue you may ask? Well, I upgrade my computer(s) VERY frequently, and since I go through NICs like candy, having a changable MAC would be beneficial.

So is there any way that can be thought of or suggestions on how to change the MAC of a NIC?

Thanks! :)
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hoov
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Post by hoov »

If you have a cable company for an ISP like Comcast then just have your router connected to your modem. Power cycle the moden off for about 1/2 hor( just a guess on the time ) . When the modem come back up it will see the router as the mac address to register with the ISP and you will be set. That way it down't matter how many computer changes that you go through behind the router :)

Hope this helps :)
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