F5F Stay Refreshed Power Users Networks Issue with pfSense router on Charter Spectrum internet, reported incompatibility with Docsis 3.1.

Issue with pfSense router on Charter Spectrum internet, reported incompatibility with Docsis 3.1.

Issue with pfSense router on Charter Spectrum internet, reported incompatibility with Docsis 3.1.

S
Sir_Flexo
Member
Find
164
03-13-2025, 05:37 AM
#1
To begin, in November 2021 spectrum replaced our modem since the current model wouldn’t fit their Docsis 3.1 network upgrade. Early on, problems emerged: the modem connected to the PFSense box but couldn’t receive DHCP data. After a month of adjustments using Charter and two different modems, connectivity improved. By mid-January, we experienced a single internet outage. Restarting both devices resolved it temporarily. About 1½ months later, on one occasion the connection failed again—requiring four restarts before it stabilized. I attempted direct PC connections before restarting, which worked. Eventually, I tried older Wi-Fi routers (2014–2018) and found mixed results; some still connected, others didn’t. Spectrum indicated potential hardware issues, suggesting the modem might not support Docsis 3.1 anymore. They also mentioned IPv4 usage after leaving the RJ45 port. They advised checking compatibility with a PFSense dedicated PC. My question: is PFSense Docsis 3.1 compatible? If not, what further troubleshooting steps should I try before they confirm incompatibility? Thanks! Modem details included.
Reply
Reply
S
Sir_Flexo
03-13-2025, 05:37 AM #1

To begin, in November 2021 spectrum replaced our modem since the current model wouldn’t fit their Docsis 3.1 network upgrade. Early on, problems emerged: the modem connected to the PFSense box but couldn’t receive DHCP data. After a month of adjustments using Charter and two different modems, connectivity improved. By mid-January, we experienced a single internet outage. Restarting both devices resolved it temporarily. About 1½ months later, on one occasion the connection failed again—requiring four restarts before it stabilized. I attempted direct PC connections before restarting, which worked. Eventually, I tried older Wi-Fi routers (2014–2018) and found mixed results; some still connected, others didn’t. Spectrum indicated potential hardware issues, suggesting the modem might not support Docsis 3.1 anymore. They also mentioned IPv4 usage after leaving the RJ45 port. They advised checking compatibility with a PFSense dedicated PC. My question: is PFSense Docsis 3.1 compatible? If not, what further troubleshooting steps should I try before they confirm incompatibility? Thanks! Modem details included.

Reply
Reply
A
AloyLP
Junior Member
Find
48
03-13-2025, 05:37 AM
#2
Pfsense operates as a router operating system. It doesn't rely on docsis. Your modem depends on docsis to transform your internet link from coaxial to Ethernet. Pfsense simply accepts that Ethernet link. The problem appears to involve DHCP; what's unusual is that computers establish connections while the routers remain unreachable. For testing, I'd attempt to assign a static IP on Pfsense. Plug the modem into your computer, note the IP, gateway, and subnet mask, then configure them in Pfsense. This helps eliminate the actual link and confirms DHCP is the culprit. I'm assuming both the AMD desktop and HP laptop are using Windows. I'd suggest letting Spectrum know that the direct modem (WAN) works on Windows but not through any router.
Reply
Reply
A
AloyLP
03-13-2025, 05:37 AM #2

Pfsense operates as a router operating system. It doesn't rely on docsis. Your modem depends on docsis to transform your internet link from coaxial to Ethernet. Pfsense simply accepts that Ethernet link. The problem appears to involve DHCP; what's unusual is that computers establish connections while the routers remain unreachable. For testing, I'd attempt to assign a static IP on Pfsense. Plug the modem into your computer, note the IP, gateway, and subnet mask, then configure them in Pfsense. This helps eliminate the actual link and confirms DHCP is the culprit. I'm assuming both the AMD desktop and HP laptop are using Windows. I'd suggest letting Spectrum know that the direct modem (WAN) works on Windows but not through any router.

Reply
Reply