STP - Not needed - http://www.dd-wrt.com/wiki/index.php/STP - The Spanning Tree Protocol (STP) is a method of preventing loops at layer 2 (data-link) of the OSI model.
Host Name -
Domain Name -
Use DNSMasq for DNS -
DHCP-Authoritative -
Boot Wait - Not needed really, for downloading new firmware - http://www.dd-wrt.com/wiki/index.php/Glossary
DDNS
Type - ? no idea (Static,Dynamic,Custom...)?