Arris SBG8300 SURFboard Modem/Dual-Band Router

Let me start by saying I have worked in the IT industry for going on 35 years in all areas from software development to networking and systems infrastructure. I have experience configuring routers/load balancers for Fortune 500 companies that run as much as $75K each for managing worldwide global networks, so I'd say I know what I'm doing. I have been using a Motorola Arris Surfboard SBG6900 configured as an edge/perimeter device routed to an ASUS RT-AC68R router for the internal network to isolate everything except selected devices from the external network and use port forwarding on the Arris to the ASUS to expose those selected devices to the public internet as needed. Namely, a staging web server with FTP services for clients to access. It has worked FLAWLESSLY for over 5 years. Recently I upgraded my internet to achieve faster speeds with unlimited data and as a result, had to upgrade my cable modem from a DOCIS 3.0 to a DOCSIS 3.1 model. I had been so happy with the Arris 6900 that it seemed to be a no-brainer to go with the Arris 8300. This has been a frustrating and disappointing total waste of time. First off, the firmware/software version loaded onto the unit out of the box is broken. The screens where you define port forwarding settings are not even correct. They are missing fields so you cannot map external ports to internal ports. You can only specify a start and end port which is useless in terms of security, and even then, the port forward simply DOES NOT WORK. After running a few hours, the unit automatically downloads an upgraded version of the firmware/software (from SDK 7.0 to SDK 7.1) which corrects the admin screens so port forwarding can be set up properly. Even so, after configuring the port forwarding on this 8300 STILL DOES NOT WORK. I have been fighting with this thing for a week. The very first thing I did was to check with my ISP after having them activate the new modem to ensure no ports were being blocked. Of course, none were. I have performed multiple factory resets and reconfigured them from the ground up. Double, triple, and quadruple-checked my configurations, and nothing will make this POJ forward traffic according to the defined port-forwarding rules. I even bypassed the internal router and connected directly to the new unit to isolate and rule out any possible failures with other equipment, which seemed unlikely because the ONLY thing that had changed was the modem. You can't even SSH into the router itself to see what's going on with this unit, meaning you can't inspect routing tables/port mappings in any attempt to correct the problem at the OS level. Finally, I got on the phone with Arris customer support. My last experience with them was over 5 years ago and I was very satisfied. They were professional, knowledgeable, polite, and extremely helpful - no more. I explained in detail everything I had attempted, my network configuration, equipment isolation, the multiple factory resets, etc. What did they do? He listened with half an ear and then proceeded to read his troubleshooting script and ask me to do all of the things I had already done multiple times. At each step, I told him I'd already done that and that it would not work, but he kept saying 'I know you said you did it, but I have to document it.' I could barely understand the guy and he was getting on my very last nerve, but I humored him and did everything he asked. Finally, after he tried everything in his silly little script, he put me on hold for 15 minutes before coming back on the line and telling me my problem was my TEST SERVER! That didn't go down well, especially since I can hit that server from my internal network and it works fine, and not to mention everything worked fine up to the point I hooked up their new modem. Following that, I considered the possibility I had gotten a "lemon." I initiated a return/exchange with Amazon, which they fulfilled promptly, and received the new unit yesterday. The result? Exact same second verse as the first. In my research during the week I have been doing battle with this POJ, I read that Arris is aware of the fact that their admin interface for this unit does not work properly but they won't say when or even IF they will fix it. Their customer service wouldn't even consider the possibility that something may be wrong with the device. If they're going to sell a cable modem/router combo with a basically useless router, they should sell it at the price of a basic cable modem. These are NOT cheap units, but they DO SUCK. I'm returning BOTH of these POJs and will never buy another Motorola modem again. Following many recommendations I've read in the last week, I've ordered a NetGear Nighthawk cable modem/router combo. It's about $100 more expensive, but at least the reviews are good. For those who want a plug-it-in and forget-it type of unit, the SBG8300 should be fine. Internet speed, wi-fi and streaming have been good with the unit, but if you want to manage/configure your network using advanced features, forget it.