Two Broadcasts - One Coaxial Network


Hope everyone is having a good year.

I have spent countless hours watching YouTube trying to figure this out and have a solution that works but wondering if there is a better configuration/solution to the problem.

The goal

Achieve ethernet connection in a room (the room) that only has a coax outlet that is nowhere near the internet gateway.

The problem:

Two conflicting broadcast domains,

Two ISPs: First ISP provides only cable/OnDemand television and uses coaxial cable to broadcast the network to the TVs (which seems to be unstoppable - whatever it is connected to it broadcasts the signal into). Second ISP provides only internet service and receives its signal from a different coaxial cable from outside i.e. there are two different coaxial cables coming into the house and the cabling that runs throughout the house is used only to broadcast the TV network.

The TV gateway is in bridge mode and cannot be taken out of bridge mode. Disabling DHCP on the TV gateway is also not an option as this messes with the TVs. The TV gateway is MoCa capable.

FYI: The TV and Internet gateways are already on two different subnets i.e. their network IPs are totally different.

The solution I do not like:

When the I plug the Internet gateway into the TV gateway (that all coax outlets in the house receive their signal from) using an ethernet cable and then connect a MoCa ethernet adapter to the coax outlet in the room - then I can connect to the Internet gateway via a static IP address/gateway (i.e. I cannot connect via DHCP, if DHCP is enabled I still connect to the TV gateway but with a static config I can access the internet gateway and therefore have an internet connection) - however then the existing computers that are directly connected to the internet gateway, when the DHCP lease expires, connect to the TV gateway via DHCP and therefore lose internet connection (the TV gateway has no internet). I can solve this by having the computers connected directly to the internet gateway configured with static IP/gateway addresses so they will never use the DHCP from the TV gateway - problem solved but I do not like this solution.

The solution that caused another problem:

Instead of connecting the gateways via ethernet, I used another MoCa adapter to connect the internet gateway to the ‘IN’ port of a coax splitter and then plugged the TV coax and TV gateway to the ‘OUT’ ports. I was then able to connect directly, from the room, to the internet gateway using DHCP - I did not need to use a static config - however this caused all the TVs in the house to lose their OnDemand internet connection (cable TV still worked) - also the computers connected to the internet gateway remained connected to the internet gateway even when their DHCP lease expired - I think having the TV coax cable plugged into the ‘OUT’ port of the coax splitter prevents the signal from travelling to the internet gateway and also prevents the TV gateway from sending a DHCP signal out into the TV coax cable. Solution does not work.

The current solution that works:

After countless hours of watching MoCa and networking videos, I thought what might solve this problem is router; so I got an edgerouterX and stuck it between the TV gateway and Internet gateway. I plugged the internet gateway into WAN port and the TV gateway into the LAN port and voila! I can now access the internet from the room using a static IP/gateway config and the computers connected to the internet gateway do not receive the DHCP from the TV gateway and continue to use the DHCP from the internet gateway that they are connected to. Problem solved? I am not sure because I still have that TV gateway plugged into the router and its pumping those TV signals into it (although it isn’t causing any problems I want to be sure that the internet is segmented from that darn TV broadcast network) so I played around with the firewalls on the edgerouterX and managed to lock myself out multiple times and came to a firewall configuration that works, I have the standard firewall setup and including a LAN interface to direction ‘local’ with default action as drop (allow established/related) and it is dropping packets!?? So this leads me to believe that darn TV broadcast is still pumping signals into the router and I am wondering if the firewall I set up is good or if I should make changes/add to the firewall etc. or if there is a better solution.


The ethernet connection in the room works no problems but curious if I can make this solution more secure (i.e. changes to the firewall?) (the internet connection cannot be mingled with the TV network - not sure if it is or not with this current set up) or if there is a better way.

Thank you very much for your time and help, it is very much appreciated.

Have a good day,

Your final solution with the router in between is a correct method - probably the only one. You have to split up the broadcast domains, and that’s a router by definition.

I would have no concerns about security, or of the TV broadcast (likely multicast) packets spilling over from the TV network to the internet network. The EdgeRouter is going to receive those packets but it isn’t going to retransmit them.