Please help me with my complicated setup. I am getting DHCP issues.

[jannie]

I have a(n old) triple story concrete house with limited cabling possible. Here is a diagram of my my setup with which I am getting reasonable coverage. I have fairly limited networking knowledge.

I think there is a clash between the Google Mesh router DHCP and the Zyxel modem DHCP. The Google mesh is in a different range than my home fixed IP addresses. So maybe I can manually change the range to the correct one and get rid of the Zyxel DHCP??

Please help!

[MichaelP]

Hello @jannie 

That certainly is complicated. You have two layers of NAT router+firewall, each of which is creating a new network behind the network it is connected to. The Zyxel "modem" is the first layer. It is connected to the internet via your ISP and is creating an intermediate network on the 10.0.0.x IP address range, and it looks like you have a fair amount of equipment connected to that network. Then, you also have a Google (or Nest?) WiFi Router connected to this intermediate network. It is also a NAT router+firewall, and is creating an inner network in the 192.168.86.x IP address range. It looks like you only have WiFi devices connected to that network. Other than being behind double-NAT, this should work for those devices to connect to the internet. But, since you have a firewall in the middle of your network, there will be limitations on how devices on the 10.0.0.x network and devices on the 192.168.86.x network can communicate with each other.

What problem are you having, exactly? 

[jannie]

Thank Michael.  Very informative. I think I have solved my problem (see below), but I have a few questions to which I would appreciate an answer:
1. Why do you say there is a firewall in the middle of my network? What is performing that? The Ubiquity, in Bridge mode?? 
2. I have not been worrying about communication between the Google Nest router-connected devices and the 10.0.0.x network devices, except that I am able to see my PCs PLEX library from a TV on the Google wifi. So that seems OK!?

My exact problem was a duplicate DHCP issue reported on my Fing box resulting in an inability to reliably list my connected devices. Also, I could not reliably connect to my IP camera. I finally found the problem though. By accident, because of a previous configuration, I had the gateway on the (FOSCAM) camera set to 10.0.0.3 instead to 10.0.0.1  It's taken me months to find this issue!

[MichaelP]

Hello @jannie 

The Google mesh router is a firewall between your 10.0.0.x network and the 192.168.86.x network it creates. It will block incoming connections (from 10... to 192...), but will allow outgoing connections (from 192... to 10..., which is how those hosts get to the internet through your "outer" firewall). That's how those hosts are able to get to your Plex library, since it's an outgoing connection. This will also block "autodiscovery" protocols that rely on multicast within a single network. But, it sounds like you aren't relying on that. Just keep it in mind if you ever run across something that wants to use that feature.

Really glad to hear you found your issue, though!

[jannie]

Aha, so the initial connection direction is the important issue, not the data flow direction. Very illuminating. For interest then, if I did want to see a 192... device from a 10... device, is the only option to change the Google range to 10..... ?

[MichaelP]

Hello @jannie 

Right - it's the initial connection direction that matters for this type of firewall.

To connect from outside to inside, you would need to open a port mapping, essentially punching a very small and very specific hole in the firewall to allow connections to a range of ports on the external IP address to be mapped to one of the inner hosts.

Since it's a router and firewall, you can't make the internal and external IP address ranges part of the same network (e.g., 10.0.0.x). If it was a "bridge" instead of a router+firewall, it would be transparent to this issue, but it wouldn't support having multiple secondary access points as part of a mesh interconnect.

[jannie]

Thanks so much for explaining this so clearly. I will look up how to open port mapping on the Google Nest router in case I ever have to do that.

Best Regards

Jan

[AbigailF]

Hey folks, 

Thanks for lending a hand, @MichaelP and @Jeff.
@jannie, I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any concerns or questions from here, as I would be happy to take a closer look and assist you further.

Thanks,
Abi

[LovelyM]

Hey everyone, 

I appreciate the help, Abi. 

@jannie, I know it has been a while, but I wanted to ensure that everything is covered here. If you have other questions in mind, let me know. 

Best, 
Lovely

[Dan_A]

Hey there,

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns as I will be locking this thread in 24 hours.

Cheers,

Dan

[Jeff]

Thanks for the info and explanation, MichaelP.

Hi jannie,

I just wanted to jump in real fast to see if you saw MichaelP's reply and to see if you still needed some help on this or if you were able to get it sorted out. If you are still needing some help, just let us know and we'll be happy to continue helping.

Thanks,
Jeff

[Jeff]

Hey jannie,

I just wanted to follow up once more to see if you were still needing some help here. If so, just let us know.

Thanks,
Jeff

[jannie]

Thank Jeff, I think I have finally solved the issue (and learned a lot more about networking)! See the answer to Michael above.