How to change a cable modem's IP address fast?

I'm on DSL now and its so easy to change the IP address by just using the modem's software to Disconnect then Connect which generates a new IP address in a few seconds.

But soon I'll have to switch to a cable modem and the only way I found before of changing the IP address was to unplug the LAN cable from the motherboard and plug it into a network card which produced a new IP address. If I stayed off the IP address of the motherboard for about 24 hours or more it would tend to give me a new one when I plugged it back in again. I'd love to be able to do this with the modem though. Wondering if this is possible.
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More about change cable modem address fast
  1. It not really the hardware platform that causes that. It depends how the ISP has set things up. You to a point are just lucky (if you like your ip changing) that the dsl does not change. The one in my rent house I needed to leave off for days to get the ip to change.

    My current one has a sorta fixed ip. It will only change when they restart their service which only happens a couple times a year.

    Cable modems have the additional issue that the modem itself is doing part of the security. It is mapping its mac address to the PC mac address. It is the cable modem mac that the ISP uses for security. This is why people have to reboot the modem when they plug one pc in and then change to another. I guess if you wanted to you could change the mac on your PC in the nic settings and then use a power strip that lets the PC turn the modem on and off. That would be your best bet to get a new ip......but you never really know it varies a lot from ISP to ISP
  2. My DSL IP can change because I log into the modem's software and change it. Otherwise I could just unplug it and when it reboots it seems to always have a new IP. Logging in is just far quicker. 5 seconds and Poof....I'm born again online.

    I'd love to be able to do the same with my future cable modem service. Unplugging the network cable between network cards and the motherboard is a real hassle. And I have to use an IP from my local area so I can't use some foreign proxy server.
  3. Not to insult you, but are you sure you aren't confusing your WAN address with your LAN address. It has been that in my experience, the WAN address rarely changes. You can change LAN addresses at will.
  4. I suspect he is talking wan address. Some DSL you can get to change the IP just by resetting it. I know of one guy whose business is dependent on that. He offers basically to spam craigslist with ads. To get around craigslist restrictions he keep multiple DSL connection in multiple hosting centers and constantly resets them.
  5. Yes, its the Wan address but it does change the IP address.
    I'd love to be able to do the same with a cable modem.
  6. I've been on time-warner for at least 8 years now. The only time my IP changes is when they add a new node or make other changes on their network. Unplugging the modem for a day seems to do nothing. I suspect their DHCP lease times are turned up pretty high.

    This is my experience with time warner in my location anyhow. Others may be different.
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