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cpt-pat asked

Is there any way to remotely recover from Internet connectivity locked on WiFi instead of Ethernet?

I have Internet connectivity for my Cerbo device using ethernet as a primary and WiFi as a backup (per the default behavior described in the manual).

A month ago, there was a momentary AC power outage that shut down my ethernet router. Connectivity automatically switched to WiFi. Good!

When power was restored, connectivity failed to revert to ethernet and remained on WiFi.Then, 6 days ago, the WiFi radio lost connectivity with the provider, but the WiFi access point remained active. Now, all my Cerbo data is being sent to a doomed WiFi connection and I have lost all connectivity to VRM. Bad!

I am in Europe while my installation is in California. Can anyone think of a way to recover? The only option I have is to reboot the ethernet router by asking someone to power cycle the AC at my installation. Will loss and recovery of the ethernet port on the Cerbo trigger the Cerbo to switch back to the ethernet port, or is the Cerbo behavior contrary to the description in the manual?

cerbo gx
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Alexandra avatar image Alexandra ♦ commented ·
@Cpt Pat

Not remotely with no connection to the gx.

There is a handy feature on the gx for when you do get it restored. It is to reboot at a specific interval when there is no contact with the vrm.

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cpt-pat answered ·

Success! After 9 days of rebooting every 4 hours, the Cerbo finally selected the ethernet port over the WiFi connection, restoring control. I was able to the reconfigure the Cerbo to "forget" the non-functional WiFi network.

From this experience, I infer that the Cerbo is only testing for link-layer connectivity and it is not testing for network-layer WAN (Internet) connectivity; and that in my case at least, it greatly prefers the WiFi interface over the ethernet interface.

And @JohnC , you were correct: the inactive interface can be determined by "--" appearing in the gateway field.

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cpt-pat answered ·

The root of my problem is:

1) The Cerbo is preferring WiFi and is not reverting to using a working ethernet connection.

2) The WiFi access point is running, but it has no connectivity.

3) Even though the Cerbo is configured to reboot every 4 hours when there is no connectivity to VRM, each time, it chooses the WiFi for connectivity. It has latched onto WiFi.

4) There is no way to configure the Cerbo to prefer ethernet over WiFi connectivity even though the manual says that is the default behavior (there also is no way of remotely determining which connectivity, ethernet or WiFi, is being used when connectivity does exist).

6) I am 7,000 miles away.

My Cerbo is running off the vessel's batteries, so power is never interrupted.

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Alexandra avatar image Alexandra ♦ commented ·
@Cpt Pat

The point in the manual is not that the cerbo prefers ethernet over wi-fi it is that ethernet is preferred to wifi as it is less fickle, to connect to a router. Although on your case it seems more dominant.


Wi-Fi is an inherently less reliable connection than a hardwired ethernet cable. It should always be a preference to connect via ethernet when possible. Signal strength should always be at least 50%.

Not that this helps you right now. I can only imagine the frustration.

An interesting suggestion about being able to choose the preferred connection by the user though.

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JohnC avatar image JohnC ♦ commented ·
@Cpt Pat

You can tell which is working by it's Gateway address. The one that isn't will revert to '---', even though it may show 'Connected'.

You can delete a wifi connection by telling it to 'Forget Network'. To get it back you need the Wifi Key as a password.

Using a CCGX I just tested the ethernet preference on different lan subnets, and it indeed returns to ethernet as per the manual.

Are you sure your ethernet connectivity is actually working? And yeh, I'm sure it's tough to troubleshoot over a distance..

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cpt-pat answered ·

Thanks John. Since I can't reach the device, I can't be sure, but I recall seeing a gateway address shown in the configuration for both the ethernet and WiFi (which both happen to be 192.168.1.1) when the ethernet connection was in use. Both addresses are DHCP assigned, not statically configured.

I'm sure the ethernet connectivity is up because I have other devices (a camera) using the same router that are currently up.

If I ever regain connectivity, I will first confirm a gateway address for the ethernet port, cross my fingers and hold my breathe, and then "forget" the wireless paring. With the Cerbo rebooting every 4 hours, maybe that will happen someday.

After this experience, I've learned that WiFi cannot be trusted as a backup for connectivity.

This is a difficult test case: to simulate my situation you'd have to:

1) Establish erthernet connectivity.

2) Establish WiFi connectivity.

3) Interrupt ethernet connectivity to cause a failover to WiFi, and then reconnect the ethernet interface.

4) Without dropping the WiFi paring and signal (to keep the WiFi interface active), remove Internet connectivity from the WiFi router.

5) See if the Cerbo switches back to ethernet connectivity.

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