Wireshark is an essential tool for network analysis, allowing users to capture and interactively browse the traffic running on a computer network. At computernetworkassignmenthelp.com, we offer expert assistance to students tackling complex Wireshark assignments. This blog post presents two master-level Wireshark questions, complete with detailed solutions, showcasing the expertise of our professionals. If you find yourself struggling with similar assignments, remember that you can always rely on us to "write my Wireshark assignment" and ensure top-quality results.
Question 1: Analyzing TCP Traffic for Performance Issues
Problem Statement:
You are tasked with analyzing TCP traffic between a client and a server to identify performance issues. The network captures include several retransmissions and duplicate ACKs. Your objectives are to:
1. Identify the sequence number of the first retransmission.
2. Determine the round-trip time (RTT) of the TCP handshake.
3. Calculate the average throughput of the TCP connection.
4. Suggest potential causes for the observed retransmissions and duplicate ACKs.
Solution:
Step 1: Identifying the Sequence Number of the First Retransmission
1. Open the provided packet capture file in Wireshark.
2. Use the filter `tcp.analysis.retransmission` to isolate retransmitted packets.
3. Locate the first retransmitted packet and note its sequence number.
In our capture, the first retransmission occurs at packet number 1057 with a sequence number of 3046721.
Step 2: Determining the RTT of the TCP Handshake
1. Use the filter `tcp.flags.syn==1` to locate the SYN packets initiating the TCP handshake.
2. Identify the three-way handshake packets: SYN, SYN-ACK, and the final ACK.
3. Calculate the RTT by subtracting the timestamp of the initial SYN packet from the timestamp of the SYN-ACK packet.
In our capture, the initial SYN packet is at timestamp 0.000000 seconds, and the SYN-ACK packet is at 0.001234 seconds. Therefore, the RTT is approximately 1.234 milliseconds.
Step 3: Calculating the Average Throughput
1. Filter the traffic between the client and server using the appropriate IP addresses: `ip.src==client_ip && ip.dst==server_ip`.
2. Calculate the total bytes transferred and the duration of the transfer.
3. Average throughput is given by the formula: \( \text{Throughput} = \frac{\text{Total Bytes}}{\text{Total Time}} \).
In our capture, 1.2 MB (1,200,000 bytes) of data was transferred over 10 seconds, resulting in an average throughput of 120,000 bytes/second or 120 KB/s.
Step 4: Suggesting Potential Causes for Retransmissions and Duplicate ACKs
Several factors can cause retransmissions and duplicate ACKs, including:
- Network Congestion: High traffic loads can lead to packet loss.
- Faulty Network Hardware: Defective routers or switches might drop packets.
- Suboptimal Network Configuration: Misconfigurations can lead to inefficient routing and packet handling.
- Interference: Wireless networks can suffer from interference, causing packet loss.
By addressing these areas, you can mitigate the retransmissions and improve network performance.
### Question 2: Evaluating HTTP Performance Over TLS
Problem Statement:
Analyze the performance of HTTP traffic over a TLS-encrypted connection. Your tasks include:
1. Extracting the certificate information used in the TLS handshake.
2. Measuring the time taken to establish the TLS connection.
3. Evaluating the HTTP GET request and response times.
4. Providing recommendations to optimize the performance of HTTP over TLS.
Solution:
**Step 1: Extracting Certificate Information**
1. Filter the TLS handshake packets using `ssl.handshake.type == 11` (Certificate).
2. Locate the certificate packet and expand the details in the packet details pane.
3. Extract the subject, issuer, and validity period of the certificate.
In our capture, the certificate has the following details:
- Subject: CN=www.example.com
- Issuer: CN=Example CA
- Validity Period: Valid from 01-Jan-2024 to 31-Dec-2024
Step 2: Measuring TLS Connection Establishment Time
1. Identify the initial ClientHello packet using the filter `ssl.handshake.type == 1`.
2. Locate the ServerHello packet and note the timestamps.
3. The time taken to establish the TLS connection is the difference between these timestamps.
In our capture, the ClientHello packet is at timestamp 0.000000 seconds, and the ServerHello packet is at 0.056789 seconds, giving a TLS connection establishment time of approximately 56.789 milliseconds.
Step 3: Evaluating HTTP GET Request and Response Times
1. Filter HTTP traffic over the established TLS session using `http && ssl`.
2. Locate the HTTP GET request and note its timestamp.
3. Identify the corresponding HTTP response and calculate the time difference.
In our capture, the HTTP GET request is at timestamp 0.123456 seconds, and the response is at 0.223456 seconds, resulting in a response time of 100 milliseconds.
Step 4: Recommendations for Optimizing HTTP over TLS
To optimize the performance of HTTP traffic over TLS:
- Session Resumption: Utilize session resumption mechanisms like session IDs or tickets to reduce handshake overhead.
- HTTP/2: Upgrade to HTTP/2, which offers improved performance through features like multiplexing and header compression.
- TLS 1.3: Adopt TLS 1.3 for faster handshakes and improved security.
- Caching: Implement caching strategies to minimize redundant data transfer.
Conclusion
Wireshark is an invaluable tool for network performance analysis and troubleshooting. Through these master-level questions and solutions, we've demonstrated the depth of analysis possible with Wireshark. If you need expert help to "write my Wireshark assignment" and achieve similar in-depth insights, computernetworkassignmenthelp.com is here to assist. Our professionals are well-equipped to handle complex network analysis tasks, ensuring you gain a comprehensive understanding and excellent grades.
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