Perbandingan antara menggunakan kurang kurawal {} dan tidak.
Ternyata untuk website2 intenasional, kyak Yahoo dan temen deketnya tidak menyukai nat berdasarkan device.
Berdasarkan pengalaman, YM sama mail.yahoo jadi lelet dan kadang gk mau di buka klo natnya pake {}

contoh nat yg running well :

nat on $ext_if inet from -> $ext_ip
nat on $ext_if inet from -> $ext_ip
nat on $ext_if inet from -> $ext_ip
nat on
$ext_if inet from !$ext_if to -> $ext_rad

rdr on $int_if inet
proto tcp from to any port $redirect -> $proxy
rdr on $int_if inet
proto tcp from to any port $redirect -> $proxy