Troubleshooting • Raspberry Pi 5 + Google WiFi: Sounds like a NAT issue, but doesn't seem so

Hi All,

I tend to have a raspberry at home running some services (ssh, svn, apache, vpn) that I can access from the outside world. A few days ago I upgraded my hardware from a raspberry pi 3 (RPi3) to a new raspberry pi 5 (RPi5) and started migrating all these services to the new raspberry. (This upgrade was an opportunity as I was running low on SD-card space in RPi3.)

Furthermore, for my network at home I have Google WiFi (mesh; indeed Google WiFi, not Nest, nor Nest Pro) and I manage everything via the Google Home App. My internet provider is AT&T and I am using an IP passthrough so that everything is managed by the Google WiFi devices.

After purchasing the RPi5, initially everything was fine. I could ssh, commit and update my svn repos, see webpages being served by apache, and use wireguard (I used to work with OpenVPN in the previous raspberry). So, all the port forwarding would occur as expected and the services were running fine.

Fast forward 1-2 days later, I did not like the LAN IP of the RPi5 and I tried to assign a new LAN IP to my RPi5. However, the RPi5 would not obtain the new "dedicated" IP upon reboot, unless, I would give:However, this would be unstable! After a reboot, I could see RPi5 getting the old IP (with some probability -- not always), which was not meant for it, and naturally port-forwarding would break. So, I decided to go back and allow RPi5 to have the LAN IP it showed preference. Around the same time I installed OpenVPN as well -- let's say due to a friend's suggestion.

After the above two events (fixing the LAN IP to what RPi5 wanted and installed OpenVPN), RPi5 would not offer many services, or offer them intermittently. In particular, I can no longer login at the RPi5 at home via ssh from the outside world. However, I can do so, if I redirect incoming traffic to port 22 to the old RPi3 that is running at home.

Same is true for apache. Should I redirect my incoming requests to the new RPi5, I can see a message "Invalid Host header". Should I redirect incoming requests to port 80, then RPi3 serves content as expected to the outside world!!

Coming back to ssh, sometime today morning I started getting a "connection refused" message for attempts that I did in order to login via ssh using the LAN IP of RPi5. In other words, even if I am not attempting to reach the brand new RPi5 from the outside world, I may still find the door closed while I am on the same LAN!

Troubleshooting steps that I have tried:

• I have tried using as main router two out of the three Google WiFi devices that I have and the result is identical in both of them.
• Port forwarding to the same/similar services offered by the wanna-retire RPi3 works great! However, not so for RPi5.
• I have completely uninstalled both Wireguard and OpenVPN. Both had been installed via pivpn.

Other observations:

• I noticed that when RPi3 joined the network, I would get a message through the Google Home App telling me that the particular device called, say, "RPi3" has joined my network. However, this never happened when I used RPi5 -- I never got such a message (and I made sure that I would plug into the network the RPi5 alone as I was testing for this purpose).
• Along these lines, RPi3 would appear as "RPi3" in the list of devices shown through the Google Home App, but RPi5 would be recognized as "unknown" device and I would have to specifically find the RPi5 and give it a name through the Google Home App. So, perhaps there is some issue with some "bonjour" (or something ...) service? This is odd, given that RPi5 is the "latest and greatest"! One would find reasonable the opposite observations, but not this.
• ssh may work intermittently for RPi5 even if I am on the same LAN!
• Now that I have RPi5 on the network, I find the Google Home WiFi to behave oddly. In particular, it may show in the app that the network for my home is "Offline" and in case this is true, then I cannot make any changes on port forwarding, reserving IP addresses for devices, etc. This typically does not last long, or may stop being an issue if I specifically try to find the devices in the app and then going back to the previous screen would show the network to be in "Great" shape. By the way, I have internet access on my devices when this issue occurs. So, I am thinking it should be something in RPi5 that is really confusing the Google WiFi router. But what would that be?

Does anyone have any idea on what might be causing this issue and more importantly how it can be resolved? Any ideas on what troubleshooting steps we can take to figure out what is wrong? All help is more than welcome!

Statistics: Posted by MightyMouse314 — Fri Mar 15, 2024 3:42 am

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