Two LANs, How to Inter-Access?
 

I have two LANs that used to be one LAN. The original (LAN1) is at my house. I have a DSL internet connection, which is fine for me. I have a wireless bridge set up that extends LAN1 to my son's house that is about 3/4 mile away. My son was using my LAN1 for internet connectivity.

My son now has a fibre connection and no longer is on LAN1, but the wireless bridge is still in place to service a switch and couple of arduino data collection devices that I have set up there (it is part of our farm).

What are my options to be able to use my son's internet connection (call it LAN2) on the rare occasion that my DSL is down or when I want to download something big fast (like an O/S image). I'd like to have it so that I don't need to change settings, etc., on his router.

So, what options do I have?

What terminology should I be using? Then, at least, I'd know what to search for!

Other advice?

Thanks,
JP.

If you can ping your son's router then it should be just a matter of changing the route i.e gateway device.
Otherwise, we need more information on how the bridge works.

Right now there is no physical connection.

When the fibre was installed a new router / access point was installed (a Calix GigaSpire Blast).

The old switch / access point that I installed in the house is still there but currently powered down.

Both of the LANs are set up on 192.168.1.x subnet (is that the correct terminology?).

P.S.: I will whip up a quick drawing of the topology.

A drawing would help.

Hopefully this works.

https://www.linuxquestions.org/quest...1&d=1705430318

The red switch / ap is the one that is powered down. It is phisically sitting right beside the Calix GigaSpire Blast.

I assume originally that your Son's LAN would be on the same subnet as yours?
Do the bridges have a static or assigned via DHCP?

Without knowing exactly how the bridge works i.e. if it just an extension then for DHCP devices I would assume the closest DHCP server would respond first i.e. each router which could lead to address conflicts. If you have access to both router's configuration then you can set the range in half for each network i.e. 192.168.1.1 - 192.168.1.127 and 192.168.1.128 - 192.168.1.254. One router at 192.168.1.1 and the other at 192.168.1.254. It depends on how the aarduinos are configured. To access your son's internet you would just switch the route from 192.168.1.254 to 192.168.1.1 (or vice versa depending on how it was setup).

Yes, my router, the green one, did all of the DHCP serving.

The AP's that comprise the bridge have static IP's.

The bridge is pretty transparent, from my point of view it acts like a 1/2 mile long length of cat5. Definitely not the fastest, the AP's for the bridge are 15 years old now. But very reliable and low maintenance.

That would be a lot of work, I have a lot of stuff hanging on the LAN1 192.168.1.x subnet.

If I were able to change the LAN2 (the Calix router) subnet to 192.168.2.x and then just connect my old house switch (red) to the Calix (yellow) would that work? If so to access LAN2 from LAN1 would I set up a desktop computer (for instance) with a second IP number (eg.: 192.168.1.40 and 192.168.2.25)?

You would also need to change the bridges to the 2.x subnet. A second IP address on the same network adapter would allow access but don't know or think you can route traffic to it. Maybe via firewall rules you can route traffic. A second physical network adapter would work for sure.

So if I put a second adaptor in my 192.168.1.40 desktop and hooked it to any switch I could set it up to access internet via the Calix router (which would be at 192.168.2.1).

Or, if I did not want to install a second adaptor in my 192.168.1.40 desktop, I could change the desktop networking settings to get its IP form Calix router (192.168.2.1) and when I was done switch it back to get its IP from the 192.168.1.1 router.

Right?

Yes, but I think you would need to manually configure a static ip address on the computer itself. Debian uses network manager to configure networking even with dhcp.

Just accessing the arduinos would only require adding a second ip address via the ip command.

I think that I can handle that.

You've just hit on the difficulties of my LAN. When I started out, many, many years ago, on arduinos I set the IP address in the arduino software. I had problems with that so then I started setting reserved IP addresses for MAC's in the router, which, for my purposes, works much better. Then I started adding RPi's for various purposes. Now I dread the (inevitable) day, that may or may not come in my time, when I need to replace my router. OK, it wouldn't be that bad, but I am now old and lazy. And, network administrators will cringe at this, I have a couple of RPi's (data base, music, back up, etc., servers) that are over 3 years uptime (1173 days the longest) and I just can't bear to take them down.

P.S.: michaelk, thank you for your patience, I'll let you know how it works out. JP.