ext_if="tun0"
table <internal_net> {172.16.0.0/24, 172.16.1.0/24}

set loginterface tun0

scrub in all

# altq
altq on $ext_if priq bandwidth 700Kb queue { q_pri, q_def }
queue q_pri priority 7
queue q_def priority 1 priq(default)

# NAT
nat on $ext_if from <internal_net> to any -> ($ext_if)

# altq
pass out on $ext_if proto tcp from $ext_if to any flags S/SA keep state queue (q_def, q_pri)
pass in on $ext_if proto tcp from any to $ext_if flags S/SA keep state queue (q_def, q_pri)

block in quick log on $ext_if proto tcp from any to ($ext_if) port {21 139 143 445 2000 3306 6000}