Firewall is a device that filters access to the protected network from the…
2020
Firewall is a device that filters access to the protected network from the outside network. Firewalls can filter the packets on the basis of
(A) Source IP address
(B) Destination IP address
(C) TCP Source Port
(D) UDP Source Port
(E) TCP Destination Port
Choose the correct answer from the options given below:
- A.
(A), (B) and (C) Only
- B.
(B) and (E) Only
- C.
(C) and (D) Only
- D.
(A), (B), (C), (D) and (E) Only
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Correct answer: D
Answer: A firewall can filter using Source IP address, Destination IP address, TCP Source Port, UDP Source Port, and TCP Destination Port.
Why:
IP addresses (source and destination) are in the IP header, so firewalls can match and filter traffic based on these fields.
TCP and UDP ports (source and destination) are in the transport header, so firewalls can filter by TCP source port, TCP destination port, and UDP source port.
Packet-filtering and stateful firewalls use these header fields to allow or block traffic; more advanced application-layer firewalls can inspect payloads, but that is beyond the listed attributes.
Conclusion: All five listed attributes are usable for firewall filtering, so the option that includes all of them is correct.
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