Strange IP behaviour

Hi all!

Got a "problem" I'm wondering if anyone has the answers to.
Running a C8 on platform, connected through WiFi and have DHCP set on router.

For some strange reason, every so often during reboot, voluntary as unvoluntary, the hub changes IP.
Always switching between the same two IP's.
Looking in the list of connected devices on the router, I can currently see two C8's (named by myself to keep track), but they have individual MAC-adresses?

Only real issue for me with this is that back ground pictures used on dashboard that are stored locally loses "connection" and that me and the missus needs to log out of the mobile app and log back in.
Strange, but annoying, so if anone can help?

To confirm, do you have just one C8? Or is there a second C8 unit in the mix here too?

If just one, was there ever a different C8 unit in the past? Figuring out why there are 2 unique (but consistent) MAC addresses seems important to figure out...

Nope, just the one C8. Had a C7 prior. That one had the now desired IP if that helps anything.
I can confirm that after each switch I do end up in the C8 and every device, app and rules work as they should, so Zigbee and Z-wave aren't affected.

Is the second MAC address the old C7's MAC? Did you first remove the C7's DHCP reservation before setting up the reservation for the C8 on the desired IP?

It seems like the router still wants to (at least sometimes) point to the old device, so I suspect the old DHCP reservation wasn't fully removed or turned off or whatever.

This is the design of DHCP. Leases expire. Set up a DHCP reservation for each hub. That way when the hub(s) reboot they will always have the proper IP address.

No, just checked the MAC of the C7 (that is not connected anymore). Not the MAC of "ghost hub".

May have been a little unclear. The C7 is not connected. Both reserved IP's, with different MAC's, lead to same hub.
I will test releasing the reservation for both for now and see what happens next time the power goes out (which is what unvoluntary means to me :wink: ).

Hmm, even stranger. The IP to which the hub now is connected (with the "unknown" MAC) is not reserved? Even with that it always revert to that specific IP instead of the reserved one (with the right MAC).

Also, the MAC shown in "hub details" ain't either one listed on the router. The info in "hub details" correspond to the log in IP and the sticker on the bottom of the hub though.

I keep my network tweaks super basic because I'm not smart on networking stuff, so if this was me, I would first review ALL of the DHCP reservations I currently have on the router -- verify that none of them have old or have non-current or wrong information. Remove any that do.

Then verify that the desired IP is free to use (not reserved). Then set up a new DHCP reservation (on your router) for the C8 using the desired IP and the MAC from the sticker on the bottom.

If you have "Static IP" (which is not the same as a DHCP reservation) set anywhere (router or HE settings), remove that. Stay away from Static IPs unless you really know what you're doing (I myself certainly do not) -- DHCP reservations on your router are all you really need.

I cleaned up a little in the IP reservations of the router. No old stuff that had the particular IP used, but all "clutter" was removed. Also saw now that me removing the reservation on one of the "C8's" removed it completely.
Will leave everything as-is and do a controlled reboot when I have some more time to see what happens.

You don't happen to be trying to use Wifi and the ethernet connection at the same time? Have you ever set up the Wifi on the C8 at all?

The C8 has a different MAC address for both the Wifi and hardwired ports. The hub is only designed to use one of those methods, you shouldn't use both simultaneously. That would make it show up as two devices in the router if you are trying to use both.


Oooh, that's a good call!

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I agree with @neonturbo that might be an issue. To clean things up on both hubitats, press the network reset button on the bottom of each hub for 7 seconds with a toothpick or paperclip. This will clean up any wifi connections that you are no longer using as well and prevent dual connections.

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No, WiFi only. I only connected through ethernet during setup of the C8, then it has been WiFi only.

Still only one Hubitat connected. The C7 is packed down in the C8's box in a cupboard to be used as temporary backup should anything negative happen (like thunderstorms and such).
Regarding reset, will that type of resetting factory restore the hub or only clear the WiFi?
Last Saturday we had a short powerout that ended up with me having to do a soft reset through the safe mode option, no chance that would've accomplish the same thing?

It only resets the network settings. Press and hold for 7 secondfs.

I will give it a go this upcoming weekend when I have more peace and quiet.

Ok, so I did reset the WiFi as instructed. Had to reconnect to WiFi from scratch (tricky for me, but as expected), ended up with new IP, but still wrong MAC?
I have reserved this new IP in the DHCP of the router, albeit the strange MAC.
Let's see where we end up next time it reboots.. :laughing:

The mac for wifi will be different the the mac for the lan port as they are independent devices.

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