Which of these is mandatory when configuring Cisco IOS Firewall?

A.
Cisco IOS IPS enabled on the untrusted interface

B.
NBAR enabled to perform protocol discovery and deep packet inspection

C.
A route map to define the trusted outgoing traffic

D.
A route map to define the application inspection rules

E.
An inbound extended ACL applied to the untrusted interface

Explanation:
After the ACL is defined, it must be applied to the interface (inbound or outbound). In early
software releases, out was the default when a keyword out or in was not specified. The direction
must be specified in later software releases.