Controls the behavior of the DHCP Server when offering an IP address to the client. In case of ReserveByOffer=1, the client section is written to the INI file with a lease time of 1 second when answering with a DHCPOFFER message. In case of 0, no INI file entry is made at the time of offering an IP address. Only the actual assignment (reaction to DHCPREQUEST) of the IP address creates a client section. Of course, the lease time is updated upon assignment to the requested lease time.

[Settings]
ReserveByOffer=0          ; Default: 1

This was an undocumented feature until V2.5.0.