And suddenly my ISP decided I needed a new IP address, even though I’ve paid for fixed IP address, and therefore – usually – get notified of changes to the IP address.
As I’ve just changed to new hardware, my first thought was that the RAM was defective, but once I got to the machine, this proved to not be the case. Lucky as RAM is expensive when using 16GB sticks.
Oh well… Once I contacted the ISP, they reprovisioned my cable modem, and presto – no change occurred.
My setup is as follows:
- ISP provided cable modem in bridge mode
- Cisco router that gets assigned IP address from ISP (instead of the modem)
- Internal network.
The problem is, that the connection needs to be activated when the IP is changed. The new IP is then associated with the MAC address that activates the connection. The activation is done by the first connection to the outside via a browser.
After some time, I found that the following procedure would let me get the correct IP address assigned to the modem:
- Clone the router MAC address to an PC.
- Connect PC directly to modem.
- Disconnect router from modem (pull the cable).
- Factory reset modem.
- Access admin interface of modem.
- Reconfigure modem to use bridged mode.
- Once the system comes back up, the PC should be assigned the external IP.
- Activate the connection. This makes the modem reboot.
- Disconnect PC before modem comes back up, then reconnect the router.
- Remember to remove the cloned MAC address from the PC, as two identical MAC addresses in a network might get you into network trouble.
- Update your external DNS to point to your new IP address.
Easy, once you know what to do. The trouble is remembering what to do those few times a year you need to do it.
And just for completeness sake: Changing the MAC address on a Windows 10 can be done from the adapter interface configuration, advanced tab, Network address, but that is better described here (just ignore the driver update plug): http://windowsreport.com/mac-address-changer-windows-10/