You have just created a few hundred application firewall rules on an SRX device and applied them
to the appropriate firewall polices. However, you are concerned that the SRX device might
become overwhelmed with the increased processing required to process traffic through the
application firewall rules.
Which three actions will help reduce the amount of processing required by the application firewall
rules? (Choose three.)

A.
Use stateless firewall filtering to block the unwanted traffic.

B.
Implement AppQoS to drop the unwanted traffic.

C.
Implement screen options to block the unwanted traffic.

D.
Implement IPS to drop the unwanted traffic.

E.
Use security policies to block the unwanted traffic.

Explanation:

IPS and AppDoS are the most powerful, and thus, the least efficient method of dropping traffic on
the SRX, because IPS and AppDoS tend to take up the most processing cycles.
Reference :http://answers.oreilly.com/topic/2036-how-to-protect-your-network-with-security-toolsfor-junos/