Configuring 2nd router as partial switch

Dear all,

I'm still a layman when it comes to OpenWRT, so I would appreciate it if someone could help me. My problem is that I have a set-top box that needs to be connected directly to the internet. What I would like to know is (a) if it's possible to configure one port of my OpenWrt router in such a way that my STB will work (b) and what the optimal configuration would be.

I've included a picture of my setup (in red what I still need to configure):



Define directly... ( no nat, 1nat, nodualnat?, upnp etc. ) if your not sure, just explain what works for it.....

From your post it is not clear how ROUTER2 connects to ROUTER1... did you mean wifi?

1 Like

Dear Wulfy

I'm not sure, but what I understood is that my set-top box needs a 10.x.x.x. ip adres to be interactive and by enabling the router it will end up with a 192.189.0.x?

To answer you're second question they are not connected whatsoever and don't need to be (but it would be "nice to have").


  • What do you get out of the modem? Is it terminated already? I imagine yes. So what IP you get from there.
  • How many free ports you have in the switch box?
  • Do you have two OpemWrt routers as your figure suggests or do you mean that you want to "split" it.

As a side note, for the first router I would put the PCs and Nas directly on the router and put the printers on the downstream switch.

1 Like

If this is a TV box and service supplied by your ISP, often it works though VLANs on the modem port. The TV service is a separate network inside the modem. Once you know the VLAN numbers you can configure OpenWrt so the built-in switch in the router can switch the TV VLAN out to one of its Ethernet ports which you would connect to the TV box.

1 Like

you only need 1 device that will do the routing
make sure your modem is dump & not setup to do any routing itself
hook you Device that will do your routing directly to the modem. no network switch should be there
I'm presuming you have your OpenWrt Router set and work with basic internet & WIFI at the moment

now you 2nd device you need to set this up correctly
I'm assuming by your diagram that it's connected by cable
this should be connected to an output of the Router or the network switch with the desktop 1

you could simply put another network switch here (maybe the one you had on the modem before)

if you want to use another OpenWRT Device i would recommend making it a Dump Access Point & it would act like a Network switch as well
this device would bridge all the ports to make it like a switch & setup to DHCP as a management interface
& an extra WIFI Access Point to better your WiFi coverage
is that sounding like what you want to do ?

1 Like

Once again I appreciate all the help and I’m noticing I should be more clear in defining the problem and providing relevant details.

Problem: No interactive Television on set-top box

What I understood is that the set-top box needs an external IP address (for the interactivity) and it will only get the IP address when it’s connected to the modem my ISP installed.

My setup:
Modem (only) ►Switchtbox ► OpenWrt Router (port labelled 4) ► Set-Top box

  • All connected with ethernet cables
  • Ports labelled 1-3 are reserved for a TV, digital media player and TV streaming media device

My Hardware:

  • Modem Only : CBN CV6181E
  • Switchbox : DLINK GO-SW-5G
  • OpenWrt Router: Netgear WNDR3700

Switch Ports:

Standard Switch Setup:

Relating to the above mentioned replies:
I think I’ve covered most of the questions asked and based on your replies I’ve got the feeling it’s just a simple switch setup issue in LuCI?

Yup, definitely sounds like your ISP-CPE(modem) assigns ip to set top box based based on VLAN...

Some ISP's really make it hard for customers... like everyone has their modem under their televisions...
( i do... lol )

I'm sure they would advise their customers to get a cabler to resolve this issue... ( i.e. run a dedicated straight-through wall port from WALLNEARMODEM>WALLUNDERTELEVISION )

Q-forkicks: What does their helpdesk say when you ask them about your TV being no where near your modem?

Optionally, ( I would ) Let us know your ISP name and that might help as we can track down what they are running specifically... in more technical terms....

Q: Is there a physical port on their modem labelled: "SET TOP BOX" or "TV-BOX" etc.?

Downunder.... we have a popular ISP that locks down VOIP in a similar way.... In this case.... there are upper level service credentials on the ISP-CPE... Anyone who wants to use their own router effectively loses ISPbundled VOIP without "unapproved" mods or "sketchy" double-nat.....

I rate this high when eliminating who to choose for my ISP ( not saying that you should )... just sayin.....

Does your ISP modem have a web interface with any TV settings / credentials? or alike?


A: They would suggest a Powerline set

A: My Internet service provider is Telenet, part of Liberty Global

A: No there is no physical port labelled “SET-TOP BOX” (the interactivity works, when I unplug the router and connect the cable directly to the set-top box)

A: Yes there’s some sort of web interface, but it only enables me to reset the “Pincode” of the device.

Explain this better please?

Plug cable from set top box into: where EXACTLY?

Modem ►Switchtbox ► Set-Top box (interactive)
instead of:
Modem ►Switchtbox ► OpenWrt Router (port labelled 4) ► Set-Top box (not interactive)

1 Like

Excellent! Now we have everything we need :slightly_smiling_face:

Knowing the ISP name get plenty of hits related to similar issues... so i'm sure you'll get some good responses here....

So, half way down this and onward seems to be the business... ( bridge openwrt port to WAN AKA "mini-wan-switch" ):

Another way to simply iimplement this concept might be to L2 the whole thing(openwrt-dumb-ap-ish) no dhcp.... services in same lanip range as "modem"....

( Supplimentary reading:

Solved: Vlan tagging for ISP )

1 Like

from what i can see you need to find out what vlan you need to add to the switch for the set top box
I would configure the WNDR3700 similar to dump access point using only the switch so only the 4 lan ports

so remove the wan interface's
make a new interface call it access for the time being set this up the same as lan so it has an ip of with dhcp on and part of the lan firewall group
move your computer to this port "wan" & make sure you can get access to the router via

change the lan interface from static to DHCP
plug the cable going to the modem the 1st lan port
plug the set top box into the 2nd lan port
it should get an internet ip from the modem "if it's the only router"
you need to add a vlan to the switch ports
in VLAN-ID add the vlan you need "try 3 or 4 you need this to match the vlan used in you mode & set top box"
on the lan ports that the modem & the set top box is connected to set them to tagged the others leave off
if you get the set top box to work we have everything we need to setup router 1 correctly as well