what i see with one provider is that when you start a cable modem it is a DHCP server (motorola surfoboards) handing out a 192.168.100.x Ip gatewaying to the management interface 192.168.100.1 of the modem. After the device completes network entry it converts to a bridge and you get your public IP space
i assume this is a common practice, but i dont know, we only deal with one cable company around here. I hate this joint because they MAC filter for static IP space, which if fine and good, but its an up to 24 hour provisioning time to be able to switch out a firewall. So today we went to go swap one prior to the provision, and after we put in our device and restarted their cable modem, it would never hand us anything other than the internal management range from the modem, like it never completed network entry. Called them, and their tech said he could see the physical connection, but no MAC. I kept telling him it was getting handed the management range from the surfboard, he kept assuring me the modem was strictly a bridge and contained no DHCP server ever at any point. I finally told him to reprovision the device in their system, he said it wouldnt o any good but complied. After restart it completed entry and we got public IP assignment. I assume network entry isnt the correct term for cable modems being configured once they register to the network. But is this how its supposed to work where the modem is a dhcp server (I assume i router) until the cableco says otherwise to it? Its how Ive always seen it happen. At home once, after a flood of DMCA hits, they blacklisted my modem and this was the behavior, like their system refused to let it enter and convert to a bridge. -- All parts should go together without forcing. You must remember that the parts you are reassembling were disassembled by you. Therefore, if you can't get them together again, there must be a reason. By all means, do not use a hammer. -- IBM maintenance manual, 1925
