Cable modems register with their cable routers via their MAC addresses. When the modem negotiates its downstream and upstream channels, and is then able to communicate with its CMTS bi-directionally, it begins a DHCP handshake as its first order of business.
If the DHCP Handshake does not complete for any reason, the modem will de-register from that particular CMTS, and scan the remaining downstream spectrum for another CMTS. This provision was implemented for cases where there might be multiple IP providers using the same cable plant.
Usually, however, the modem just scans through its range and comes back to the same CMTS, where it again goes through negotiations of upstream and downstream frequencies and power levels, before it makes a DHCP request again. This ranging, particularly on the upstream channel, eats up a bit of bandwidth and CMTS resources.
It appears that instead of letting unregistered or deauthorized modems continually cycle through their discovery and power level adjustments, your ISP instead gives the modem a complete DHCP handshake. Included in that handshake is the location of a modem configuration file which includes parameters like QoS, packet filters, enabled/disabled feature sets, and several other options. The file may be individually crafted by the provisioning system database (which ties into the DHCP server), or it might be a one-size-fits-all config, say for any modem for which the provisioning system has no record. The modem then fetches the config file via TFTP. If the file checks out, then the modem's registration process is complete; it will stay online and not try to re-range.
Likely, the decommissioned modem now gets a very restrictive config file, redirects all DNS queries to a proxy server that only hands out the web page you mention, and otherwise locks down the modem to keep it from being used unless it's subscription is paid.
So, until someone puts your old modem into the DB on the new account, it is effectively deactivated on that provider's network.
1what on earth.. – barlop – 2017-09-23T20:02:40.517
1MAC address and network segment authorized – Tyson – 2017-09-23T20:05:12.587
1
and by the way, somebody that writes the first paragraph that you did, doesnt care about technicalities.. but anyhow what may be relevant is that the "cable modem" can and in your case may, has a PPP function that logs into your ISP. And you can login to your router at http://someip and change it. But really you should call your ISP and ask them how to connect. And you could ask them what your old model of cable modem was if you want that one. I dont know if the issue could be mac address related. You should call your ISP and ask for tech support
– barlop – 2017-09-23T20:06:29.237@barlop Sorry if I didn't express myself the way you'd like to. Actually I did keep my old modem, that's why I think it's the MAC address that makes the CMTS choose the user inside the ISP. Also I can't find any option into the router's config webpage that allows me to change the login credentials. – Iaka Noe – 2017-09-23T20:48:35.220
@IakaNoe if you go to the command prompt and run the command ipconfig<ENTER> then it should say "default gateway" and there should be an IP there. – barlop – 2017-09-23T21:43:07.790
The ISP has to provision the modem for your service. That basically activates the MAC address and ties it to your account. Your old modem may not have enough channels to support the speed you want. Is it DOCSIS 3? Th ISP should not care and as far as I know cannot force you to use any particular equipment. But if it doesn't work with their service or doesn't support the speed you want, then you're tough out of luck. – Appleoddity – 2017-09-23T21:47:32.347
@barlop I do know that. What I'm trying to say is that there's no login option in that page as there is in other routers. – Iaka Noe – 2017-09-23T21:48:47.027
it'd help if you took a pic on your phone and included it, also make and model of cable modem.. and try resetting it too – barlop – 2017-09-23T22:43:39.840