IPTV over router issue

Question

I have an issue with the IPTV box connected in my system. Ideally, the ISP provided setup should look like this:

How I have it connected is this way:

So in practice the gateway's WAN port is connected to the ISP provided LAN port. The address range there is 192.168.1.x. On the output of the gatway, there is a sub-network with 192.168.7.x address range- the IPTV device does not like that... The IPTV device is normally assigned with a valid address (192.168.7.x) and has internet access, but the channels are blocked. The ISP technician said it has to be in the ISP provided modem range.

Right now my gateway and the access points are the Netgear Orbi RBK853 (1 main router + 2 satelites). It takes quite a while (in physical cables terms) for the ethernet connection to reach the IPTV box, since starting from the Orbi gateway there is a satelite (access point) and a switch (not drawn here). So the easiest solution, to connect the IPTV directly to the ISP provided modem is not possible for me.

How to configure the gateway (if even possible), to somehow forward the packets from the ISP provided modem directly to the IPTV box without the NAT network created by the gateway, so the IPTV box gets assigned with an IP from the 192.168.1.x range (by the ISP provided modem), instead of 192.168.7.x (Orbi gateway).

PS: I have replaced the Wifi Mesh setup I had before with Orbi just now. Physically it was connected the same way and this worked- when I logged to the gateway interface I haven't seen the IPTV box- I have seen it via the ISP provided modem interface, so it was somehow forwarded.

I tried exercising VLAN approach, but if understood correctly, I would need to sacrifice one of the physical LAN ports of my gateway for that. Since at the given lan port more devices than just the IPTX box are connected, I could not go this way. I need more of a specific mac address oriented approach.

Answer 1

I suspect it's not just the IP address; with many ISPs it's also the ability to receive multicast packets – the IPTV box sends an IGMP 'join' packet for a channel, the router forwards it up to the ISP, and you start receiving the stream for that particular channel much like a TV signal.

When that's the case, "having a 192.168.1 address" is not actually what's needed – it's a stand-in for "being directly in the ISP-router's own subnet"; looking at the IP address is merely a way of telling whether the device is in the right subnet or not.

(And that is still not the full story; really it can be in a different subnet as long as all routers in the way can forward IGMP towards the 'WAN' side and can forward multicast from 'WAN' back to the IPTV box.)

The above is not always the same for all ISPs (some use multicast and some don't), but it's rather common – so common in fact that many home routers even have the "IGMP proxy" ability even if they're otherwise entirely lacking in features. So the first thing I'd suggest trying is to enable "IGMP proxy" on your router and see if that helps.

How to configure the gateway (if even possible), to somehow forward the packets from the ISP provided modem directly to the IPTV box without the NAT network created by the gateway, so the IPTV box gets assigned with an IP from the 192.168.1.x range (by the ISP provided modem), instead of 192.168.7.x (Orbi gateway).

While technically possible, it's a lot of configuration that often isn't even available on home routers, and it'll really be easier to use VLANs.

I tried exercising VLAN approach, but if understood correctly, I would need to sacrifice one of the physical LAN ports of my gateway for that. Since at the given lan port more devices than just the IPTX box are connected, I could not go this way.

No, literally the whole point of VLANs is usually that you can have multiple on the same port. It will be the job of a (smart) switch connected to that port to demultiplex the VLANs, assigning some of the switch ports to the "192.168.7" VLAN and some to the "passthrough to ISP" VLAN.