A network analyst is reviewing a packet capture of a file transfer. The sender transmitted segments with sequence numbers 1000–1999, 2000–2999, and 3000–3999. The receiver sent an ACK for 2000, then an ACK for 2000 again, and then a third ACK for 2000. What will the sender most likely do next?

Retransmit all three segments starting at sequence number 1000

Retransmit the segment starting at sequence number 2000

Wait for the retransmission timeout to expire before retransmitting

Increase the congestion window and continue sending new data

A network engineer is troubleshooting a TCP connection that is experiencing frequent timeouts and retransmissions. The capture shows that the sender's retransmission timeout (RTO) is set to 1 second, but the measured round-trip time is 200 ms. The engineer suspects that the RTO is too aggressive. Which adjustment should be made to improve performance?

Increase the RTO to at least 2 seconds

Disable retransmission and rely on upper-layer recovery

Use the Jacobson algorithm to dynamically adjust the RTO based on RTT and variance

Why is the initial sequence number (ISN) randomly chosen in TCP connections?

To ensure the sequence number space is always exhausted

To reduce the risk of accepting stale segments from a previous connection

To enable faster retransmission

To allow the window size to be larger

What does the acknowledgment number in a TCP segment indicate?

The next sequence number the sender expects to receive

The sequence number of the last byte received

The initial sequence number chosen by the receiver

The total number of bytes sent in the connection

GIAC Certified Intrusion Analyst

Domain 1Objective 4

TCP GCIA Practice Questions (Page 2)

Part of the Network Fundamentals domain, which makes up ~35% of our current practice bank. GIAC (SANS) does not publish an official question count, but from its 240-minute exam (~95–160 total, ~33–56 in this domain), expect 7–11 from this objective — we provide 50 practice questions to prepare you well beyond it. (estimate)

50questions here

10free pages

12concepts

Questions 6–10

6application · medium
A network analyst is reviewing a packet capture of a file transfer. The sender transmitted segments with sequence numbers 1000–1999, 2000–2999, and 3000–3999. The receiver sent an ACK for 2000, then an ACK for 2000 again, and then a third ACK for 2000. What will the sender most likely do next?
Select an answer first
7expert · hard
A network engineer is troubleshooting a TCP connection that is experiencing frequent timeouts and retransmissions. The capture shows that the sender's retransmission timeout (RTO) is set to 1 second, but the measured round-trip time is 200 ms. The engineer suspects that the RTO is too aggressive. Which adjustment should be made to improve performance?
Select an answer first
8foundation · easy
In a TCP header, which field is used to verify that the header and payload were not corrupted during transmission?
Select an answer first
9foundation · easy
Why is the initial sequence number (ISN) randomly chosen in TCP connections?
Select an answer first
10foundation · easy
What does the acknowledgment number in a TCP segment indicate?
Select an answer first

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TCP GCIA Practice Questions (Page 2)

Questions 6–10

In a TCP header, which field is used to verify that the header and payload were not corrupted during transmission?

Why is the initial sequence number (ISN) randomly chosen in TCP connections?

What does the acknowledgment number in a TCP segment indicate?

Keep studying — Network Fundamentals