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Comment by tedunangst | Hacker News Reader

The technical aspects of getting this done are pretty interesting, but I don't know why you'd do it. I'm not even sure I know what it does.

I do all my routing on my router. The cable modem is just the box that turns the square cable into the round cable.

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I think it's more about getting root than adding a route. I assume the author is aware that he can purchase a separate router. DOCSIS hacking is highly frowned upon by cable companies, and the FBI. It's probably better to have a practical reason to do it, instead of "I wanted to see if I could."

If I remember correctly, an ISP can push a new firmware to a Docsis3 modem at any time too and force reboot it.

Bothers me none of my modems have ever had the option to turn off WAN-side flashing, never know who is going to figure out how to take advantage of that.

Have a SPI flasher permanently connected, and a device on the LAN connected to that flasher, and to the LAN in order to automatically detect firmware version changes. When one is detected, dump the firmware update, and reflash your preferred version, and have it match the reported version of the new update. If you have a router in front of your modem, you could even make a killswitch that blocks WAN until the reflash is complete.

Is that Pi based? I see some projects to turn a Pi into an SPI reader.

I was just theorycrafting. I’m sure it’s possible with off the shelf equipment. A rPi would be a decent choice for this.

Given the author posted it on danman.eu I would assume EU law applies. Not sure in which scenario FBI would get involved. Cause this is legal to do in EU.

I’m really curious about the fbi bit. Do you have any further reading?

When I said that I was thinking of a story from 10 or 20 years ago where a bunch of people were increasing their bandwidth by hacking their cablemodems, and they all got raided. I can't seem to find the exact story right now, but Google returns a few similar stories.

I vaguely remember this. IIRC the people raided were those hacking into the CMTS to uncap their modems and their friends modems and I want to say that at least one of them was selling services to uncap modems. Perhaps the notion of hacking was just modding the cable modem to ignore limits being given by the CMTS but either way I believe someone was selling access to this which got the attention of the feds.

That seems like an awfully terrible design if the user-controlled equipment is responsible for rate-limiting instead of the CMTS itself.

I agree. No idea if that is still possible these days. Perhaps someone here is involved in the DOCSIS standards or is a cable modem hacker and could offer some insight as to how things may have evolved.

I don't know about the FBI specifically but telecom equipment is regulated and in most places it's not legal to roll your own interface to the infrastructure. Even if you bring your own modem these days, it becomes administered remotely by your ISP. Similar to phreaking being a crime. Even if you have an agreement with your ISP, I'd expect you'd be breaking it and crossing into fraud or toll fraud at the least.

> telecom equipment is regulated

This is tricky, because "telecom" only has POTS and cable TV within its scope. "Internet" service that just uses ethernet technologies are their own separate thing, and why "Ma Bell" megacorps can get away with their junk Internet service because it's regulated differently than POTS.

> I don't know about the FBI specifically but telecom equipment is regulated and in most places it's not legal to roll your own interface to the infrastructure.

In the EU, the Directive 2015/2120 [1] enforces the ability of customers to bring their own modems, no matter if you are running fiber, xDSL or DOCSIS.

[1]: https://eur-lex.europa.eu/legal-content/DE/TXT/?uri=celex%3A...

Nice, but it's not possible to not pay cable modem rent and/or connect a different modem in practice... (Vodafone CZ)

UPC got slapped for this before it was sold to Vodafone. So for a time one could buy the modem - its pretty nasty because the rent price is exactly calculated from 2 years the company has warranty from the hw distributor. So basically if you use it for more than 2 years you are paying for payed off hardware for nothing. And of course those devices and users last far more than 2 years (more like 5-10) this is just money printing.

But other coment is right. They have to allow you use your device.

Vodafone has gotten under fire here in Germany for the same shady practice too [1]. They are seriously one of the worst providers out there... but they must allow you to connect your own modem. Get a lawyer or go to your equivalent of a consumer protection agency.

[1]: https://www.teltarif.de/zwang-zum-router-trotz-routerfreihei...

On the other hand, the EU has laws that actually guarantee users the right to use their own hardware if they want. The providers have to provide any required documentation and if the system requires devices to be registered, the providers are obliged to register user devices.

The make/model appears to be a COMPAL CH7465LG, and it's got a 1.2GHz dual core CPU, a RealTek RTL8365MB switch chip, 4 GBE ports and WiFi, so it's arguably enough of a router in it's own right.

OP has a combined router and modem, presumably without the ability to put it in bridge mode to run their own router.

I am familiar with the looks of this device as it’s in use at two locations I‘m providing in-family support for.

At least in those two cases (different ISPs), it’s possible to turn the device into bridging mode

From the screenshot at the top it looks like they're using unitymedia. The funny thing is, at least in the past, that thing resets entirely if you disconnect it from power for some time, booting up with some old firmware revision afterwards. If you power it on then and quickly access the web interface, you'll see the option for bridge mode. Then it magically updates, and the option is gone. (this was a few years ago)

As far as I know vodafone uses the same modem/router for all DOCSIS connections, but disables some funcionality (such as bridge mode) for 'ex-unitymedia' connections.

It seems like the integration of both networks is quite a task and the bridge-mode feature is not a priority. How the bridge-mode is affected by the network backbone is unclear to me. IPv6 delegation also does not work for me.

And the route itself has 192.168.88 in it which smells mighty like MikroTik to me.

To add a static route to the modem's routing table.

But why do this on the modem, why not on the router?

Looking at the screenshots of the admin panel (and the fact that pictures further down seem to show switch ports) it seems that this is a modem/router/switch combo. Unlike many providers that just provide a modem with no router functionality and just an Ethernet port.

It still would be easier to just put it into bridge mode if that's an option and use a better router, it is still an interesting hacking project!

It is the router.

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