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Router Config: 2 WANs, 2 Lans, need communication between

by ecobrett / April 26, 2018 6:12 AM PDT

Hi I've been trying to work this one out for a while with no success. This setup is in a 2-story house with 2 WAN connections each at opposite ends of the house.
Router ActionTec T3200- IP Subnet 255.255.???.0
DHCP: Required

Router ActionTec T3200- IP Subnet 255.255.???.0
DHCP: Required

Allow a home automation hub to connect to devices on both networks.

These T3200 routers don't seem to allow static routes to be configured so is this setup impossible even with the addition of a more advanced router on the network. Replacing both T3200s which provide bonded dsl connections is not an option.

I was imagining that an advanced router with the automation hub on another subnet, for example, might be possible but now I'm having doubts. Thanks for any advice!

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All Answers

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You are battling what is called....
by R. Proffitt Forum moderator / April 26, 2018 8:15 AM PDT

"Non routable IP ranges" is covered at

This is why you can't fix this with routing tables. I have run into folk that can't believe this and you give them time to ponder.

If you want to join the two networks to make a LAN, then you look into VPN solutions. But that's beyond the scope of what I'll discuss here. I may point to the VPN solution but setup must be done by the person that is going to care and support the system.

Again, the routers must support this so changes in hardware is not unusual.

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Router Config: 2 WANs, 2 Lans....clarification
by ecobrett / April 26, 2018 9:31 AM PDT

Thanks so much for your response! There's one piece of info I failed to mention. I can connect the two LANs locally, so most of the home automation traffic would stay local. However upstairs I would still want to use the upstairs WAN for internet and downstairs I would want to use the downstairs WAN. Would that still necessitate a VPN? Thanks again!

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If the LAN is connected locally.
by R. Proffitt Forum moderator / April 26, 2018 9:54 AM PDT

Then we only need to change the netmask to add addressable space so I can ping the other IP.

If the connection is over a router with two ISPs and such it is not a local connection and you fall into the non-routable IP issue. The WAN is not local and we are back to a VPN to make it so it's like we are on the other LAN.

But both LANs at the same time? A redesign would be required to bring the LANs under the same LAN. Or something entirely different than a VPN. If you can remote to a PC or such on the other LAN then you can control what ever the thing is on that PC.

Confusing at first, but at some point it will become clear that we can't route our way around this one. That is, from the above it looks like VPN or remote into a PC on the other LAN to do the controls.

--> And then we have one more (advanced to most) solution. It's to create an automation server (this is what you see in those home automation hubs) which does expose itself to the internet where a command is received and replied to the Internet and locally it talks to the smart light switch or such.

Note: Edited for grammar.

Post was last edited on April 26, 2018 9:57 AM PDT

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Router Magic
by ecobrett / April 26, 2018 12:33 PM PDT

Thanks again for the response. You inspired me to try something new that to my extreme surprise seems to work. So as I mentioned in my most recent message I wanted to communicate between LANs but continue to use respective internet connections upstairs vs. downstairs. Perhaps I could accomplish that by combining LANs...

I turned off DHCP on the upstairs router, changed the IP to match the downstairs subnet and plugged a wifi repeater connected to the downstairs router into the upstairs router. As expected upstairs devices are now getting IPs from the downstairs router DHCP. Upstairs computers have a default gateway set to the upstairs router. So it appears that the upstairs devices can communicate with the downstairs devices while using the upstairs WAN for internet.
Is this typical behavior?

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Sure. Combine the LANs but choose which gateway.
by R. Proffitt Forum moderator / April 26, 2018 12:40 PM PDT
In reply to: Router Magic

The gateway is where IP non-LAN traffic is sent. So if you want certain machines to use one router for the Internet then you change the gateway as you wish.

While I may share ideas here, I can't teach all about IP networking. That is, be sure to find articles on each area as you need more information.

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