Host with static IP does not appear in Lease Table

[seamus]

I am trying to troubleshoot a problem. I have several hosts on my network that use `dhcpcd` (DHCP Client Daemon). I've used `dhcpcd` for years, and it seems to work quite well, but I am having an issue with a couple of hosts recently that are configured with the `inform` option. All that means is that the hosts send a DHCPINFORM message, and receive a DHCPACK as shown in the log messages below.


2022-05-17T16:40:52   dhcpd[42083]   DHCPACK to 192.168.1.57 (b8:27:eb:3a:b9:78) via em1   
2022-05-17T16:40:52   dhcpd[42083]   DHCPINFORM from 192.168.1.57 via em1


`dhcpcd` seems to be happy with this result; its log shows the following:


May 17 22:40:26 raspberrypi1bp dhcpcd[265]: dev: loaded udev
May 17 22:40:29 raspberrypi1bp dhcpcd[265]: eth0: waiting for carrier
May 17 22:40:31 raspberrypi1bp dhcpcd[265]: eth0: carrier acquired
May 17 22:40:32 raspberrypi1bp dhcpcd[265]: eth0: probing address 192.168.1.57/24
May 17 22:40:36 raspberrypi1bp dhcpcd[265]: eth0: received approval for 192.168.1.57
May 17 22:40:36 raspberrypi1bp dhcpcd[265]: eth0: adding route to 192.168.1.0/24
May 17 22:40:36 raspberrypi1bp dhcpcd[265]: eth0: adding default route via 192.168.1.1
May 17 22:40:37 raspberrypi1bp dhcpcd[265]: forked to background, child pid 371


The host seems to operate correctly, `ip addr` & `ip route` give expected results, the host can reach other hosts on the LAN, and on the Internet, and the host can be found by other hosts on the LAN.

The only odd thing is that this host is never listed in the lease table when the inform option is used. I have another host that is configured identically, and it does show up in the lease table as follows:


I/f      IP addr      MAC addr           Hostname      Description               Lease type
LANem1 192.168.1.51  b8:27:eb:a7:8c:00  raspberrypi0w  RPi Zero W - WiFi client  static


I suspect that one of these two clients is failing to send something that's needed for the log entry, but I have no idea what that "something" is. Beyond the DHCPINFORM, and the DHCPACK, what is needed by the OPNsense DHCP server to make an entry in the lease table?