If I use Cisco 2911 to do NAT in production, I have not problem with inbound or outbound traffic. But as soon as I replace the router with ASA 5550 (using the above config), device does not allow inbound traffic even though I allow pretty much anything coming from outside. All inside hosts are able to reach to the Internet.
Do you know the timeout for those GARP entries?
I notice that if I use
object network WEB
nat (INSIDE,OUTSIDE) static 18.104.22.168 service tcp 80 80
device allows inbound traffic but why does it not work without port redirection?