Lease files can contain lease declarations, and also group and subgroup declarations, host declarations and failover state declarations.
Group, subgroup and host declarations are used to record objects created using the OMAPI protocol.
However, dhcpd requires that a lease database be present before it will start.
To make the initial lease database, just create an empty file called /var/lib/dhcpd/dhcpd.leases.
You can do this with: In order to prevent the lease database from growing without bound, the file is rewritten from time to time.
dhcpd.leases - DHCP client lease database The Internet Systems Consortium DHCP Server keeps a persistent database of leases that it has assigned.
This database is a free-form ASCII file containing a series of lease declarations.
Every time a lease is acquired, renewed or released, its new value is recorded at the end of the lease file.
So if more than one declaration appears for a given lease, the last one in the file is the current one.
First, a temporary lease database is created and all known leases are dumped to it.
Then, the old lease database is renamed /var/lib/dhcpd/dhcpd.leases~.
Finally, the newly written lease database is moved into place.
Lease descriptions are stored in a format that is parsed by the same recursive descent parser used to read the dhcpd.conf(5) and dhclient.conf(5) files.