DHCP pools can be out of range causing DHCP server to exit
LAN 192.168.1.1/24 with DHCP pool 192.168.1.100-192.168.1.199 working fine.
OPT1 192.168.2.1/24 with DHCP pool 192.168.1.100-192.168.1.199 working fine.
Interfaces->OPT1 - edit the IP address to 192.168.3.1/24, Save and Apply (without going to the DHCP settings and fixing those.
The system makes a new dhcpd.conf that has OPT1 with DHCP pool outside of the OPT1 subnet.
dhcpd exits complaining about this.
Thus there is now no DHCP service on any interface, even though it is only OPT1 that has a dud configuration.
It would be nice if this user "accident" did not break DHCP for every interface on the system.