ext_if="bge0"
int_if="bge1"
carp=" bge0 bge1 nfe0 "
pfsync="nfe1"

set skip on lo
set block-policy return

scrub in
nat on $ext_if from (carp1) -> (carp0:0)

pass quick on $pfsync proto pfsync
pass quick on { $carp } proto carp
block in
pass out on $int_if
pass in proto icmp all label "in"