ISC DHCP server not offering IP to specific host

[RobertKih]

I'm scratching my head with regards to a specific host that doesn't get an DHCP offer from OPNsense (24.7.10).
This has been working the previous 5 months or so for this host.

The DHCP logs points to it supplying an address:

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2024-12-11T17:07:40 Informational dhcpd DHCPOFFER on 10.7.111.107 to 28:70:ca:7b:44:88 (2870CA7B4488) via igc3
2024-12-11T17:07:40 Informational dhcpd DHCPDISCOVER from 28:70:ca:7b:44:88 (2870CA7B4488) via igc3

But when running a packet capture for that MAC address (28:70:ca:7b:44:88) there is no reply sent.

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Interface Timestamp SRC DST output
IOT
igc3 2024-12-11
15:06:08.172129 28:70:ca:7b:44:88 ff:ff:ff:ff:ff:ff IPv4, length 342: 0.0.0.0.68 > 255.255.255.255.67: UDP, length 300
IOT
igc3 2024-12-11
15:06:24.172331 28:70:ca:7b:44:88 ff:ff:ff:ff:ff:ff IPv4, length 342: 0.0.0.0.68 > 255.255.255.255.67: UDP, length 300
IOT
igc3 2024-12-11
15:06:40.172652 28:70:ca:7b:44:88 ff:ff:ff:ff:ff:ff IPv4, length 342: 0.0.0.0.68 > 255.255.255.255.67: UDP, length 300
IOT
igc3 2024-12-11
15:06:56.172830 28:70:ca:7b:44:88 ff:ff:ff:ff:ff:ff IPv4, length 342: 0.0.0.0.68 > 255.255.255.255.67: UDP, length 300
IOT
igc3 2024-12-11
15:07:12.173075 28:70:ca:7b:44:88 ff:ff:ff:ff:ff:ff IPv4, length 342: 0.0.0.0.68 > 255.255.255.255.67: UDP, length 300

Other hosts on the same VLANs get IPs as they should and I can see it both in the logs and in packet captures:

Code Select Expand

Interface Timestamp SRC DST output
IOT
igc3 2024-12-11
16:23:44.504837 04:ee:e8:1a:b1:15 60:be:b4:05:ce:5c IPv4, length 345: 10.7.111.22.68 > 10.7.111.1.67: UDP, length 303
IOT
igc3 2024-12-11
16:23:44.504991 60:be:b4:05:ce:5c 04:ee:e8:1a:b1:15
IEEE Registration Authority
IPv4, length 342: 10.7.111.1.67 > 10.7.111.22.68: UDP, length 300
IOT
igc3 2024-12-11
16:24:05.062298 04:ee:e8:1a:b1:15 ff:ff:ff:ff:ff:ff IPv4, length 342: 0.0.0.0.68 > 255.255.255.255.67: UDP, length 300

I'm confused since it has been working before...

[RobertKih]

It turned out that even though this device (waveshare POE ETH to Modbus RS-485) worked fine for several months, it had some kind of issue. With a firmware update it is back in action again.