[Sephiroth]

I'll just amplify on CC's excellent explanation above.

The modem is running on the given Dynamic IP Address as would be necessaary for the DOCSIS environment. Through that link, a GRE Tunnel is established to VM's servers. These are given the Static IP Addresses to which you are subscribed and are thus the proxy servers for your static addresses.

It's clever but a bit of a dog's dinner when you take the associated latency into account. It can't be done differently (whether L2TP or GRE) in the residential DOCSIS environment.

I have both business (Hitron) and residential services. The 16 downstream channels are identical on both modems indicating that my node hasn't yet been allocated a larger service group - or they haven't configured the CMTS to differentiate accordingly. So anything I hammer on the domestic side steals from the business side - not that I see much of that as other than a theoretical problem.