packet capture on ASA

access-list CAP_OUT_ACL extended permit tcp host 172.20.178.12 host 172.20.188.12 eq 443
access-list CAP_IN_ACL extended permit tcp host 172.20.188.12 host 172.20.178.12 eq 443
capture CAP_OUT interface WAN access-list CAP_OUT_ACL
capture CAP_IN interface WAN access-list CAP_IN_ACL

clear capture CAP_OUT
clear capture CAP_IN

sh capture
sh capture CAP_OUT