How could I reach the DHCP Leases table?

[ndejong]

How could I reach the DHCP Leases table?

[carldebilly]

After few thoughts, I think the ARP table could be a more reliable way to get the presence information I need instead of DHCP.

[ndejong]

Based on the detail you've provided "device presence detection" I'd suggest you simply need to watch the ARP tables which can be done at the pfSense console using arp -a

Adding a function to provide this would be rather easy but it is a step outside the original mission of providing a programmatic interface to pfSense to manage the config.xml file and the functions required to get that config adopted by the system.

This does not mean it's a dead-end, you should be able to use the function_call call and invoke the exec_command pfSense function to hence make an arp -a call and extract the data you need - read-the-docs, you will need to enable exec_command in the /etc/pfsense_function_calls.txt file to make this work.

Collecting the same data via a simple ssh remote-exec is your other option here.