Wireshark Lab: HTTP v8.1

Questions

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1. Is your browser running HTTP version 1.0, 1.1, or 2? What version of HTTP is the server running?
   • HTTP/1.1
2. What languages (if any) does your browser indicate that it can accept to the server?
   • en-US: English (United States)
   • en: English
3. What is the IP address of your computer? What is the IP address of the gaia.cs.umass.edu server?
   • 10.0.0.44
   • 128.119.245.12

   Figure 1. HTTP request 1

   
   

4. What is the status code returned from the server to your browser?
   • 200 OK
5. When was the HTML file that you are retrieving last modified at the server?
   • Last-Modified: Sat, 30 Jan 2021 06:59:02 GMT
6. How many bytes of content are being returned to your browser?
   • Content-Length: 128
7. By inspecting the raw data in the packet content window, do you see any headers within the data that are not displayed in the packet-listing window? If so, name one.
   • Connection: Keep-Alive

   Figure 2. HTTP response 1

   
   

8. Inspect the contents of the first HTTP GET request from your browser to the server. Do you see an “IF-MODIFIED-SINCE” line in the HTTP GET?
   • 보이지 않음

   Figure 3. HTTP request 2-1

   
   

9. Inspect the contents of the server response. Did the server explicitly return the contents of the file? How can you tell?
   • 상태 코드와 응답 헤더 및 본문을 통해 서버가 객체를 반환하였음을 알 수 있다.

   Figure 4. HTTP response 2-1

   
   

10. Now inspect the contents of the second HTTP GET request from your browser to the server. Do you see an “IF-MODIFIED-SINCE:” line in the HTTP GET? If so, what information follows the “IF-MODIFIED-SINCE:” header?
    • 이전 응답의 Last-Modified 헤더 값

    Figure 5. HTTP request 2-2

    
    

11. What is the HTTP status code and phrase returned from the server in response to this second HTTP GET? Did the server explicitly return the contents of the file? Explain.
    • 304 Not Modified
    • 객체가 If-Modified-Since 이후로 수정되지 않았으므로 서버가 객체를 반환하지 않음 (캐시 이용)

    Figure 6. HTTP response 2-2

    
    

12. How many HTTP GET request messages did your browser send? Which packet number in the trace contains the GET message for the Bill of Rights?
    • 1개 (#26)
13. Which packet number in the trace contains the status code and phrase associated with the response to the HTTP GET request?
    • #32
14. What is the status code and phrase in the response?
    • 200 OK
15. How many data-containing TCP segments were needed to carry the single HTTP response and the text of the Bill of Rights?
    • 4개 (#28, #29, #31, #32)

    Figure 7. Multi-packet response

    
    

16. How many HTTP GET request messages did your browser send? To which Internet addresses were these GET requests sent?
    • 1, 2번째: 128.119.245.12
    • 3번째: 178.79.137.164
    • 4번째: 104.98.115.146
17. Can you tell whether your browser downloaded the two images serially, or whether they were downloaded from the two web sites in parallel? Explain.
    • 요청 및 응답 시간을 보면 순차적임을 알 수 있다.

    Figure 8. HTML with embedded objects

    
    

18. What is the server’s response (status code and phrase) in response to the initial HTTP GET message from your browser?
    • 401 Unauthorized
19. When your browser’s sends the HTTP GET message for the second time, what new field is included in the HTTP GET message?
    • Authorization

    Figure 9. HTTP authentication

    
    

References

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• J. F. Kurose and K. W. Ross. Wireshark Lab: HTTP v8.1. (2021). [Word].