root@OpenWrt:~# cat /etc/config/dhcp  

config 'dnsmasq'
	option 'domainneeded' '1'
	option 'boguspriv' '1'
	option 'filterwin2k' '0'
	option 'localise_queries' '1'
	option 'local' '/lan/'
	option 'domain' 'lan'
	option 'expandhosts' '1'
	option 'nonegcache' '0'
	option 'authoritative' '1'
	option 'readethers' '1'
	option 'leasefile' '/tmp/dhcp.leases'
	option 'resolvfile' '/tmp/resolv.conf.auto'

config 'dhcp' 'lan'
	option 'interface' 'lan'
	option 'start' '100'
	option 'limit' '150'
	option 'leasetime' '12h'
	option 'netmask' '255.255.255.255'

config 'dhcp' 'wan'
	option 'interface' 'wan'
	option 'ignore' '1'
	option 'dynamicdhcp' '0'

root@OpenWrt:~#