Why does DHCP server change ip addresses on hosts in LAN?

Question

FreeBSD

Hello!
More than a year ago I installed a DHCP server on pfSense and forgot about it. This morning I come to work and see that ip addresses have changed on all nodes. How could it be? There doesn't seem to be anything like that in the settings. I had to change everything: the rules in the firewall, ip nodes in the squid, etc.
How can this be avoided in the future?

Answer 1

Well, for example, the hosts were turned off for a long time, the lease expired, the address returned to the spool. Another computer turned on, took the first free one. If there is a binding by IP, either the static is always allocated, or the lisa is bound to the poppy so that the host always receives the same IP.

Answer 2

Make static licks tied to mac. Dynamic ones could move out if hosts appeared on the network with static addresses that matched the dynamic pool. The host wants to get his old address, but he is busy and he is given the next one, well, in a bad scenario, everyone flies.