Oh Woe ISP

Given all of my work on my basement project server, it occurred to me that I would eventually need to override my router’s DNS settings if I wanted general availability through the house. I can modify the DNS settings of my desktop or laptop, but that doesn’t really scale to every cellphone, TV, media device, or other janky tech strewn around our domicile. There’s just one problem: ISP-supplied equipment does not allow that.

What they do allow (for now, anyway) is putting the modem in bridge mode, which will relegate routing duties to some external device. But of course, me being an idiot, I was reluctant to employ this solution because that meant having two devices where I currently have one. Why disrupt a working scenario? So I went in search of a consumer-supplied modem with built in wifi and routing.

During the ensuing research, I discovered that cable modems—even if they’re DOCSIS 3.1 compatible—have tiers of capability. I checked my ISP and they had helpfully upgraded my account to 1200 Mbps at some point. This is when I discovered that most modems can’t handle more than 1000 Mbps, and it’s only the hilariously expensive ones that do. This included the current device from my ISP.

So I figured since I’m not using the extra capacity anyway, I didn’t need it. I went into my account and chose to downgrade my speed to 1000 Mbps, and that triggered a new contract agreement. After everything was said and done, our bill would be about half, and all I had to do was return my modem. But first, I needed a replacement!

My ongoing research had unearthed several potential candidates, and I eventually stumbled across a great deal on a Motorola MG8702. Once it arrived two days later, I started the install process and that’s when the real pain began. The app that is supposed to add the modem to my account failed, and it wasn’t very forthcoming about the reason. So I contacted support and spent two hours mostly watching my modem reboot. The CSR eventually stopped responding, but it was probably for the best.

My second attempt was through the phone, and this time, a nice young lady informed me that my old modem was still associated with my account. Despite signing a new agreement. Despite receiving a return label for the old modem. As a result, the system wouldn’t allow another modem to take over. Once she identified that root problem, she just had to flip my new contract from pending to complete, and reassign the modem. Success! Three hours later, I finally had working internet again.

Or did I? My mobile devices and desktop did, but that was all. My basement lab machines and VMs run on a separate subnet because I’m not a psychopath. I like to maintain order, so I have a kind of numbering system where I reserve network blocks for intents. So I have a block for base systems that run my network, one for transitory VMs, one for experiments, and so on. I can’t rattle them off from memory, but it’s far less arbitrary than randomly assigned addresses.

Why does this matter? It turns out Motorola modem routers are hard-coded to a netmask of /24. This means I have about 240 addresses to work with rather than the 62,000 my network had come to expect. I literally have dozens of VMs and containers of various description, and sometimes I’ll create 20 or more to test a cluster design. This was pure idiocy. This is clearly a dumbed-down consumer device, despite the fact it has tons of advanced router settings I’ve never even heard of. Why the address restriction?

So I put it away for the night and dove in again the next morning. I finally bit the bullet and decided to use my old TP-Link router in lieu of the modem’s built-in routing function. But wait! I still had to switch the modem to bridge mode or relegate myself to a hellish purgatory of a network within a network. This can work, but introduces certain complexities I’d rather avoid.

I finally gave up three hours later, a broken and defeated man. Either my ISP doesn’t allow customer-supplied equipment to operate in bridge mode, or the MG8702 is simply a festering pile of refuse. Bridge mode never presented an IP address to the router, and I didn’t want to operate within a double NAT. The Motorola had to go. I figured my best avenue would be to eliminate bridge mode entirely and get a plain modem with no extra bells or whistles.

Since I was so demoralized, I checked the local Walmart for any DOCSIS 3.1 compatible devices and they happened to have Arris SURFboard SB8200 modems in stock. Reviews on these are mixed, but they’re about half the size of the Motorola and… actually work. I plugged everything in, used the ISP app to add it to my account, and it bestowed my router an IP address within minutes. I’ll be returning the Motorola for a refund now that everything is working, and silently curse its ancestry for good measure.

And so I ended up right back where I started. If I had simply elected to use two devices from the beginning, I would have saved roughly a day worth of troubleshooting and frustration. This is the same setup necessary for a Fiber connection, and we’ve had one of those before. I was just so happy to have everything in a single device, going backward seemed silly.

But is it really? Modems act as signal decoders, and routers handle the network. I’m using the same TP-Link wireless router as when I had a Fiber connection in another house, and I could keep using it. Sure I may outgrow it eventually, but then I can simply upgrade it and leave the modem as-is. I also secretly wonder if I should have set the ISP modem to bridge mode, but the Arris will pay for itself in three months.

I’ll just chalk this up as a learning experience and call it a day.

Until Tomorrow