although i see your question not spicific !!!
but lets say u can leave an ASA firewall without ACL
if u have the folloiwng simple network
egde firewall
two interfaces inside and outside
users connected to inside with higher securty level
other networks like internet connected to outside with lower security level
only u need internal users to access the internet or the inetwork behind the outside interface
u may need to configure proper NATing only
this case u dont need ACL
good luck
if helpful Rate
