Raspberry Pi gets a 192.168.x.x address, but rest of my home network is 10.21.179.x

Question

There is a lot of history here, so please bear with me.

Our home network used to be fine when we were with Comcast, but we wanted better speed and reliability, so we switched to FIOS. At that point, the Wifi connections from my Raspberry Pis stopped working. I got frustrated after a couple of weeks of trying to discover the cause of the problem and eventually put it aside.

The other day, I started to configure a new Raspberry Pi 4 that I plan to use on my new Sphero RVR. I set it up following the usual directions and the Pi connects to the Internet without problem over WiFi, but I can't ping it from my Windows 10 desktop.

So I started digging. I downloaded the Fing app onto my Pixel 3 Android phone and looked at the network. I immediately noticed that all the devices now have a 10.29.179.xxx addresses. That easily explains why I can't ping from my PC to the Raspberry Pi. They aren't in the same address space.

I did discover that I can ping the Raspberry Pi if I use the IPV6 address. I can even get PuTTY to connect using the IPv6 address, although I was unable to successfully login. I don't know what is causing the login problem, but it's probably something mundane.

I suspect that I can make my Rpi conform to the rest of the network using a static IP address, but that might cause problems if I take the robot somewhere else to demonstrate what it can do. What I would like to understand is why most of my network, using DHCP, is on the 10.xxx network and the Raspberry Pis seem to wind up with 192.168.1.xxx addresses.

One further wrinkle. We have two routers, the FIOS router, and a LinkSys WRT1900AC, which is the router on which WiFi is enabled.

I suspect this problem is caused by having the two routers or by something inherent in the way the Raspberry Pi interacts with DHCP.

I would like for my Raspberry Pi to configure with an IPv4 address I can use, no matter what network I am connecting it to, and I'd like to understand why this problem is happening in the first place.

Let me know what additional information you'd like to see.

* Additional Notes *

As to the comment that I have not done research. I spent a week reading through stackoverflow problems and reading up on documentation of DHCP without finding the answers to my question. I do not ask questions idley. I ask questions when I cannot find answers and need the help of people more expert than myself in the areas in which I am having trouble.

I have solved the login problem. It was a stupid password mistake.

So now I can login, over wifi, using the IPv6 address, but not with the IPv4 address.

On the FIOS router, both the 2.4 and 5GHz wifi channels are turned off.

Answer 1

As suggested by Ljm Dullaart, the problem was that there were two DHCP servers on the network. After I turned off the FIOS DHCP, my problems went away.