DHCP ports open although DHCP is deactivated in GUI

[flu]

I am using pfsense 1.2-RELEASE
My configuration is 4 NICs:

WAN*                  ->  sis0
OPT1(WAN2)          ->  sis1
LAN*                    ->  fxp0
OPT2(LANguests)    ->  fxp1

WAN and WAN2 are configured for load balancing.
LAN and LANguests are two separate LAN networks.

DHCP server on OPT2(LANguests) is activated and on LAN interface the DHCP server is deactivated,
but /tmp/rules.debug shows following rules for LAN interface:

allow access to DHCP server on LAN

anchor "dhcpserverlan"
pass in quick on $lan proto udp from any port = 68 to 255.255.255.255 port = 67 label "allow access to DHCP server on LAN"
pass in quick on $lan proto udp from any port = 68 to 192.168.xyz.1 port = 67 label "allow access to DHCP server on LAN"
pass out quick on $lan proto udp from 192.168.xyz.1 port = 67 to any port = 68 label "allow access to DHCP server on LAN"

These rules should not exist!

I do not need DHCP-Client on WAN interface and have not configured the hostname in DHCP client configuration.
Why does the following rule exist then?
pass in quick on $wan proto udp from any port = 67 to any port = 68 label "allow dhcp client out wan"

Thanks!