Heroes of Packet Analysis Quiz

Enter the competition and match your skills to those of the Packet Analysis Heroes! Answer all questions correctly for a chance to win a $500 Amazon Gift Card.

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9: Looking at the packets in the tracefile, which of the following statements is true (choose one)?

Question Background:

Two servers are connected to different server switches (L2). The two server switches are connected to the same distribution switch (L2). The distribution switch is connected to the core switch that provides the routing function in this network. Some retransmissions are detected on the servers and the source of the retransmissions need to be found. RFC’s 792 (ICMP), 793 (TCP), 2001 (Fast Retransmissions), 2018 (SACK) and 2883 (DSACK) can be helpful in answering this question.

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A. The packet with sequence number 49 (frame 4) was received out of order by host
B. Frame 14 is a retransmission of frames 4, 5, 6, 7, 8 and 11 because these frames were not received by host
C. Frame 4 was dropped by an intermediate network device, therefor frames 5, 6 and 7 generated 3 duplicate ACKs that triggered the fast-retransmission in frame 14.
D. The ICMP redirect in frame 16 was caused by a wrongly configured subnet-mask on host

The correct answer was…

A. The packet with sequence number 49 (frame 4) was received out of order by host

The contest is closed, therefore we won’t take into account any more answers.

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Who asked the question:

Sake Blok

Founder of SYN-bit

Sake has been analyzing packets for over 15 years. While working for a reseller of networking equipment, he discovered many bugs in devices from multiple vendors and presented his findings to the vendors to fix the issues. He also discovered many configuration issues that have led to functional problems or performance issues in applications running over the network. These issues were then resolved based on the reports presented to his customers. In 2009, Sake started the company SYN-bit to provide Network Analysis and troubleshooting services to enterprises with a complex IT infrastructure.

During his work Sake started developing functionality for Wireshark. Things that he missed while working with Wireshark in his day-to-day job. He also enhanced multiple protocol dissectors to suit his analysis needs. In 2007 Sake was asked by Gerald to join the Wireshark Core Development team.

Answer all questions correctly for a chance to win a $500 Amazon Gift Card.

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