Not necesarily. Use change mac addy and host name for wan port on router. But do this only after you have turned your modem off first then change router then turn modem on. That will report to cablem modem different mac addy connected to it. Quoting: Chases Tumbleweeds
Not following your concept on that one. (not the "what or where", but the "what to do" that you are saying).
Change the MAC to, what?
[link to kbserver.netgear.com
No Internet With New Router, Computer, or Adapter: MAC Spoofing
This document is relevant if you had an Internet connection, but lost it when:
* Adding a router to your network, or
* Using a different Ethernet adapter card or computer than the one your ISP used during installation.
Use ISP Configuration to see whether you need to "spoof a MAC address" to connect to your ISP. If so, follow the instructions in this document.
If the Ethernet card that was used during ISP installation is not available, you may need to register the new Ethernet card's MAC address with your ISP for the following to work.
MAC address stands for Media Access Control address (not "Macintosh computer"!), a unique number built into modems, routers and other network hardware. It ensures that one piece of equipment is not mistaken for another one. Some ISPs validate your connection by checking the MAC address of the Ethernet adapter in computer that was registered during ISP installation. If you add a router or change computer or Ethernet adapter, these ISPs will drop your Internet connection, because they find the MAC address of the newly added router or adapter, instead of the one they expect.
To fix this, change the router to report the Ethernet adapter's MAC, instead of its own. This is called "spoofing the MAC address".
To find a PC's or Macintosh's MAC address, see How to Find an Adapter's MAC address.
To Spoof a MAC Address
1. Connect the computer that your ISP's installers used to establish Internet connection to the router.
If you are unsure which computer was used, call your ISP, and ask what MAC address was registered. Then, using the instructions in the box below find the computer whose MAC address matches their records.
2. Disconnect other computers from the router.
(If you do not want to disconnect other computers, you need to know the adapter's MAC address, as described in the box below. Then, in step 6, type Use This MAC Address, entering the adapter's address.)
3. In an Internet browser type the address 192.168.0.1.
4. Type admin for the username, password for the password, and click OK.
5. Go to the Basic Settings > Router Mac Address.
6. Select Use Computer MAC Address.
7. Click Apply. This automatically gives the router the computer's MAC address.
8. Click Test to make sure you are connected. If you are not connected, contact your ISP.
That will should change your cable modems ip. Make sure to turn off cable modem while you are doing this when router is all setup turn it back on.
If this fails it is because your isp uses hostname instead of mac address to keep track.
But try this first most isps use (media access control)=mac addresses to keep track of things connected to their cable or dsl modems.