[Solved] Iot Device Not Geting DHCP Lease

[Pocket_Sevens]

Good afternoon all.  Could use some hints on how to troubleshoot an issue.

I've got an IoT Device that, as of March 4th, stopped receiving a DHCP lease from the Router.  Checking the ISC DHCPv4 logs, this is what I see for the devices MAC Address:

2024-03-04T10:18:21-05:00   Informational   dhcpd   DHCPACK on 192.168.1.149 to 10:7b:<snip> via re0   
2024-03-04T10:18:21-05:00   Informational   dhcpd   DHCPREQUEST for 192.168.1.149 (192.168.1.1) from 10:7b:<snip> via re0

I haven't changed my setup nor has there been any firmware update on the device itself (that I know of).  Since my AP is separate from my OPNSense router, I can see the device connected to the AP; but, the IP is listed as "Unknown" at the AP.  The device doesn't show up in the DHCPv4 leases page at all on the router.

It's the only device in my network that is not getting an IP address.  Every other device (and IoT device) is getting an IP address.

I am currently on 24.1.3_1.  I have Unbound set to a DNS server using DNS by TLS with some ad blocking blocklists.  I'm also running Zenarmor for some other advanced filtering.

Any suggestions on where I can look for issues would be greatly appreciated.  Thanks.

[meyergru]

Are you sure that this is not just a glitch at your AP?

Can you ping the device? From the log, it looks like the device requests a prolongation of the DHCP lease (REQUEST), which is immediately granted (ACK). No problem so far.

If that lease does not show up at the router, it may be because of a static assignment for that MAC.

BTW: If by any chance this really does not work, try rebooting your AP, especially if this is a Unifi device. I had one Unifi AP ignore one specific client recently.

[Pocket_Sevens]

Hey meyergru.  Thanks for the reply.  I originally had a static setup for the IoT device but then deleted the static assignment.  Either way, I'm still not able to ping the device.  Something happened on 3/4 that it's no longer getting a DHCP lease.

I've also rebooted my mesh network a few times.  The mesh AP setup can see the device - it's just not getting a DHCP lease in OPNSense. 

I've switched to the new KEA DHCPv4 setup and still no joy.  I've done the static reassignment to see if that will help.  What's interesting is there's another IoT device from the same manufacturer that's having the same issue - and it's only those 2 devices from that manufacturer that's causing me grief.  Every other IoT device connects without issue.  Very strange.

Well, we soldier on...

[meyergru]

If you have two devices from the same manufacturer with the same problem, and the OpnSense is obviously sending out a DHCP ACK, then maybe those devices do not pick up the response because of something special in it.

It was recently discussed that DHCP is a quite complicated protocol (which was the main reason to relaunch ISC DHCP as KEA). Even though I have some experience with it, I was astonished to learn that a client can request specific extended attributes because of the length restriction on DHCP packets. When you look at /var/dhcpd/etc/dhcpd.conf, you may find some option(s) that you changed or which have been added recently to the file generation which disturb your clients.

[Pocket_Sevens]

Good morning meyergru.

Last night, I downgraded back to 23.7.12_5 (tried to revert to 24.1.2 but it was a disaster) via a fresh install (thankfully, I keep point-in-time backups before major upgrades).  Even that didn't seem to work for the affected devices.

So, I'm thinking now that it's a device problem and I'm reaching out to the manufacturer to see if they pushed anything recently that could have affected their devices.

Thank you for all of your guidance on this issue.  I'll mark this thread as "Solved" since it's more of a device problem than it is an OPNSense problem.