How to configure different IP classes on the WAN and LAN

[Braavos]

I would like to configure a secondary network which must be separate from the primary network. The Orbi router will act as DHCP server through one of the LAN port. The secondary network will be 172.19.255.0 and gateway IP will be 172.19.255.254.

The internet link on the Orbi router will come from the primary network. The IP will be a private one but in different network say 10.10.10.0.

The challenge is when I configure 10.10.10.x as Orbi internet, I am getting an error that the IP is not valid because the LAN network is 172.19.255.0. Again if I set the LAN gateway the same as the router IP then it means I can reach the primary network while on the secondary network

How do I configure both Orbi WAN and LAN independently and still have internet on the secondary LAN. 

[CrimpOn · Accepted solution]

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@Braavos wrote:

Thanks @CrimpOn , for your prompt reply, so in short if  I have one public IP from the ISP I cannot use it on the router and still create a DHCP on the Orbi LAN?

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It is probably useful to confirm how many "routers" we are talking about.

ISP's provide one public IP address to a customer.  That is the WAN (internet) IP address on the router.  The router in turn creates a private IP network on the LAN side.  One router: one LAN network.

A second router (perhaps an Orbi) can be connected to one of the LAN ports on the primary router.  The WAN IP address on that second router will get an IP address from the primary router.  It will then create its own LAN side network, with a different IP address space.  All of the devices connected to that second router will have different IP addresses than everything connected to the primary router.  This is commonly described as a "Double NAT" situation: https://kb.netgear.com/30186/What-is-Double-NAT 

I have stacked as many as three routers.  Devices on the third router can access the internet, but there are major complications getting them to access devices connected to the first two routers and things such as internet gaming, opening ports, VPN, etc.

So, each router has one WAN IP and creates one LAN network.

[CrimpOn]

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@Braavos wrote:

I would like to configure a secondary network which must be separate from the primary network. The Orbi router will act as DHCP server through one of the LAN port. The secondary network will be 172.19.255.0 and gateway IP will be 172.19.255.254.

.....

How do I configure both Orbi WAN and LAN independently and still have internet on the secondary LAN. 

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The Orbi product DHCP server can only handle one DHCP pool and the default is to assign the LAN IP of the Orbi as both the gateway and the DNS server.  Orbi cannot distinguish a DHCP request broadcast by which LAN (or WiFi) interface it comes from.

I am afraid that this design is not compatible with the Orbi product capabilities.

[Braavos]

Thanks @CrimpOn , for your prompt reply, so in short if  I have one public IP from the ISP I cannot use it on the router and still create a DHCP on the Orbi LAN?

[Mstrbig]

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@Braavos wrote:

Thanks @CrimpOn , for your prompt reply, so in short if  I have one public IP from the ISP I cannot use it on the router and still create a DHCP on the Orbi LAN?

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When you say public IP, did you purchase this IP, so it is static? Or is it the assigned IP address from the ISP, that may change from time to time?

[CrimpOn · Accepted solution]

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@Braavos wrote:

Thanks @CrimpOn , for your prompt reply, so in short if  I have one public IP from the ISP I cannot use it on the router and still create a DHCP on the Orbi LAN?

---

It is probably useful to confirm how many "routers" we are talking about.

ISP's provide one public IP address to a customer.  That is the WAN (internet) IP address on the router.  The router in turn creates a private IP network on the LAN side.  One router: one LAN network.

A second router (perhaps an Orbi) can be connected to one of the LAN ports on the primary router.  The WAN IP address on that second router will get an IP address from the primary router.  It will then create its own LAN side network, with a different IP address space.  All of the devices connected to that second router will have different IP addresses than everything connected to the primary router.  This is commonly described as a "Double NAT" situation: https://kb.netgear.com/30186/What-is-Double-NAT 

I have stacked as many as three routers.  Devices on the third router can access the internet, but there are major complications getting them to access devices connected to the first two routers and things such as internet gaming, opening ports, VPN, etc.

So, each router has one WAN IP and creates one LAN network.

[Braavos]

@CrimpOn thanks a lot, I now fully understand the capabilities of the Orbi router. A private IP from the ISP/primary router is required and the LAN on the Orbi router will be on the network range of the private IP.

[Braavos]

@Mstrbig thanks, I meant a public  IP from the ISP which is normally a static IP.  I didn't  mean a private/local IP from the ISP router