Good Day, lpacukovski
You can use DHCP to bind an IP address to a specified MAC address to prevent users in the from changing their IP addresses and generating IP address conflicts or unauthorized usage of IP addresses.
For further details, please see the following link:
If you want to increase the duration in seconds that a conflicting IP address is removed from the DHCP range before it may be reused, use the following CLI commands to increase the timer:
# config sys dhcp server
# edit "ID"
# set conflicted-ip-timeout "Value in seconds" -> Enter an integer value from <60> to <8640000> (default = <1800>)
I hope this helps you meet your requirements.