• Use internal DNS - Allow dnsmasq to be your DNS server on LAN.
• Use received DNS with user-entered DNS - Add DNS servers received from your WAN connection to the static DNS server list (see Network configuration).
• Prevent DNS-rebind attacks - Enable DNS rebinding protection on Dnsmasq.
• Intercept DNS port - Any DNS requests/packets sent out to UDP/TCP port 53 are redirected to the internal DNS server. Currently only IPv4 DNS is intercepted.
• Use user-entered gateway if WAN is disabled - DHCP will use the IP address of the router as the default gateway on each LAN.
• Ignore DHCP requests (…) - Dnsmasq will ignore DHCP requests to Only MAC addresses listed on the Static DHCP/ARP page won't be able to obtain an IP address through DHCP.
• Maximum active DHCP leases - Maximum allowable active DHCP leases at one time.
• Static lease time - Absolute maximum amount of time allowed for any DHCP lease to be valid.
• Custom configuration - Extra options to be added to the Dnsmasq configuration file.

DHCP Client (WAN):

• DHCPC Options - Extra options for the DHCP client.
• Reduce packet size - Needs explanation.

Other relevant notes/hints:

• The contents of file etc/dnsmasq.custom are also added to the end of Dnsmasq's configuration file (if it exists).
• When using “dhcp-option=6”, “Use Internal DNS” and “Intercept DNS port” must be un-checked