A packet filtering firewall looks at the data packet to get information about the source and destination addresses
of an incoming packet, the protocol (TCP, UDP, or ICMP), and the source and destination port for the:

A.
desired service.

B.
dedicated service.

C.
delayed service.

D.
distributed service.

Explanation:
Packet filtering is a firewall technology that makes access decisions based upon network-level protocol header
values. The filters can make access decisions based upon the following basic criteria:
Source and destination port numbers (such as an application port or a service number)
Protocol types
Source and destination IP addresses
Inbound and outbound traffic direction
Incorrect Answers:
B: A packet filtering firewall can grant access to desired services, not dedicated services, through source and
destination numbers.
C: A packet filtering firewall can grant access to desired services, not delayed services, through source and
destination numbers.
D: A packet filtering firewall can grant access to desired services, not distributed services, through source and
destination numbers.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, p. 630