NetBSD-5.0.2/dist/ipf/rules/server

#
# For a network server, which has two interfaces, 128.1.40.1 (le0) and
# 128.1.2.1 (le1), we want to block all IP spoofing attacks.  le1 is
# connected to the majority of the network, whilst le0 is connected to a
# leaf subnet.  We're not concerned about filtering individual services
# or 
#
pass in quick on le0 from 128.1.40.0/24 to any
block in log quick on le0 from any to any
block in log quick on le1 from 128.1.1.0/24 to any
pass in quick on le1 from any to any