What version of Ubuntu are you running? newer (desktop) versions use dnsmasq via NetworkManager as a local relaying DNS server - you should see it running if you look at the port with netstat or lsof:
$ sudo lsof -i :53
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
dnsmasq 2222 nobody 4u IPv4 12335 0t0 UDP localhost:domain
dnsmasq 2222 nobody 5u IPv4 12336 0t0 TCP localhost:domain (LISTEN)
If it annoys you, afaik you can remove it (at least on 12.04 that was possible). Not sure what you mean by scrapping rc.local?
dnsmasq is a lightweight DNS, TFTP and DHCP server. It is intended to
provide coupled DNS and DHCP service to a LAN.
Dnsmasq accepts DNS queries and either answers them from a small,
local, cache or forwards them to a real, recursive, DNS server. It
loads the contents of /etc/hosts so that local hostnames which do not
appear in the global DNS can be resolved and also answers DNS queries
for DHCP configured hosts.