GIAC Exam GCED Topic 8 Question 45 Discussion

Actual exam question for GIAC's GCED exam

Question #: 45
Topic #: 8

[All GCED Questions]

When running a Nmap UDP scan, what would the following output indicate?

AThe port may be open on the system or blocked by a firewall

BThe router in front of the host accepted the request and sent a reply

CAn ICMP unreachable message was received indicating an open port

DAn ACK was received in response to the initial probe packet

Show Suggested Answer

Suggested Answer: C

In a case study of a redirect tunnel set up on a router, some anomalies were noticed while watching network traffic with the TCPdump packet sniffer.

Packets going to port 25 (Simple Mail Transfer Protocol [SMTP] used by mail servers and other Mail Transfer Agents [MTAs] to send and receive e-mail) were apparently taking a different network path. The TLs were consistently three less than other destination ports, indicating another three network hops were taken.

Other IP header values listed, such as fragment offset. The acknowledgement number is a TCP, not IP, header field.

by Myra at Jul 12, 2024, 10:40 AM

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Kristeen

1 months ago

I'm going with C. An ICMP unreachable message was received indicating an open port. That's the only one that really makes sense to me.

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Eden

6 days ago

I agree with you, C) An ICMP unreachable message was received indicating an open port seems to be the correct answer.

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India

7 days ago

I'm leaning towards B) The router in front of the host accepted the request and sent a reply.

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Vashti

9 days ago

I think A) The port may be open on the system or blocked by a firewall is more likely.

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Margery

1 months ago

Ha! I bet the person who wrote this question is a real prankster. They're trying to trick us with these answers.

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Azalee

4 days ago

C) An ICMP unreachable message was received indicating an open port

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Tabetha

7 days ago

B) The router in front of the host accepted the request and sent a reply

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Gilma

1 months ago

A) The port may be open on the system or blocked by a firewall

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Mertie

2 months ago

Wait, are you sure? I thought the correct answer was A. The port may be open on the system or blocked by a firewall. I'm a bit confused here.

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Cory

15 days ago

I'm not entirely sure, but I believe it could be either A or C. It depends on the specific situation.

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Desirae

25 days ago

Actually, it could also be C. An ICMP unreachable message was received indicating an open port.

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Anglea

1 months ago

I think the correct answer is A. The port may be open on the system or blocked by a firewall.

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Cordelia

2 months ago

Hmm, I think the answer is B. The router in front of the host accepted the request and sent a reply. That's what the output seems to indicate.

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Marion

13 days ago

I'm leaning towards D. An ACK was received in response to the initial probe packet.

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Jerry

15 days ago

I agree with B. The router in front of the host accepted the request and sent a reply.

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Lizbeth

26 days ago

I believe it's C. An ICMP unreachable message was received indicating an open port.

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Ceola

2 months ago

I think the answer is A. The port may be open on the system or blocked by a firewall.

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Carylon

2 months ago

I'm not sure, but I think C) An ICMP unreachable message was received indicating an open port could also be a possibility.

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Rory

2 months ago

I agree with Glennis, because the output shows that the port is either open or blocked by a firewall.

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Glennis

2 months ago

I think the answer is A) The port may be open on the system or blocked by a firewall.

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