# block all traffic by default
block all

# allow outgoing traffic
pass out on en0 inet proto { tcp, udp } from any to any keep state

$ sudo pfctl -s rules
No ALTQ support in kernel
ALTQ related functions disabled
block drop all
pass out on en0 inet proto tcp all flags S/SA keep state
pass out on en0 inet proto udp all keep state

/usr/bin/sudo ifconfig pflog0 create

block all log

/usr/bin/sudo tcpdump -i pflog0