Similar to security contexts, Cisco ASA can be enabled for transparent firewalls from the CLI. Consult Chapter 10, "Transparent Firewalls," for configuration steps.
Figure 19-26 shows how to set up an EtherType ACL on ASDM if the security Cisco ASA is already running in transparent firewall mode. Navigate to Configuration > Features > Security Policy > Ethertype Rules and click Add. Figure 19-26 shows an ACE being set up to allow all inbound IPX traffic to enter the inside interface. Because there is an implicit deny at the end of an ACL, all other traffic will be denied.
Figure 19-26. Setting Up an EtherType ACL