-K, --dhcp-authoritative
Should be set when dnsmasq is definitely the only DHCP server on a network. For DHCPv4, it changes the behaviour from strict RFC compliance so that DHCP requests on unknown leases from unknown hosts are not ignored. This allows new hosts to get a lease without a tedious timeout under all circumstances. It also allows dnsmasq to rebuild its lease database without each client needing to reacquire a lease, if the database is lost. For DHCPv6 it controls the same behaviour as DHCPv4 with missing leases (except for the RFC uncompliance - the DHCPv6 RFCs allow this behaviour if configured). It also sets the priority in replies to 255 (the maximum) instead of 0 (the minimum).