pfSense router issue with charter spectrum internet service, claimed not docsis 3.1 compatible

pwrobot · February 17, 2022

To set the stage, back in November 2021 spectrum replaced our modem because our existing unit was not going to be compatible with their docsis 3.1 network they were upgrading too. From the start they had issues. The modem showed a link with the pfsense box, but it would not get any DHCP data from it. After a month of trying things with charter and trying 2 different modems we got the network to work. Fast forward 1 1/2 months to mid-January, we lost internet one day for some reason. I restarted the modem and router and as expected it started working again. A week later it happened again, and this time it took 4 restart cycles to get it working right. After this I hoped it would be the last time, I had to do this again about 5 days later. I am a curious person and before restarting anything i tried connecting a computer directly to the modem and it had no issues getting internet. I was puzzled and followed my restart procedure to get our internet working. Again, it went but I could get internet by directly connecting. So, I decided to try my spare Wi-Fi routers from 2014 to 2018. 3 different units reported no connection on the wan from the modem, but in-between changeovers before restarting the modems I plugged a computer directly into the modem and got a working connection. I decided to reach out to spectrum, and they say that the hardware may be faulty, so I took it to a different location and it worked fine including my pfsense box. I then reached out to spectrum again and they claimed that our router is probably not docsis 3.1 compatible and will no longer work. To my understanding once the internet leaves the rj45 port on the modem it is not using the docsis protocol but using ipv4. The cable representative eventually was willing to send a tech out after 3 multiple hour-long phone calls with them, but requested I validate that a pfsense dedicated PC is compatible with a doksas 3.1 cable modem. So, my question is, is pfsense docsis 3.1 compatible (as requested by spectrum) and does anyone have any other troubleshooting things I can try if they cannot get anything working in the near future?

Thanks!

Modem: hitron en2251

PFSense box info

pc engines pc: apu4c4 (4Gb ram, AMD GX-412TC CPU)

PFsense community edition version 2.4.4-release-p3

other devices tested to check for modem internet connection

AMD fx desktop (successful internet connection)

HP ProBook laptop (successful internet connection)

ASUS rt-acrh13 (no network cable attached error)

ASUS rt-ac86u (no network cable attached error)

Netgear prosafe VPN firewall fvs338 (no network cable attached error)

mtz_federico · February 17, 2022

pfsense is a router os. It does not use docsis. Your modem uses docsis to convert your internet connection from coaxial cable to ethernet. pfsense just takes that ethernet connection. the issue seems to be with DHCP, the weird thing is that your computers are getting a connection but not the routers.

For testing I would try to set a manual ip on pfsense. Connect the modem to your computer, write down the ip, gateway and subnet mask and set them on pfsense. This rules out the actual connection and confirms that the issue is with DHCP.

I am asuming that both the AMD desktop and the HP laptop are running windows. I would tell spectrum that the direct modem (wan connection) is working on windows but not on any router.