Lab 5-1 Select one UDP packet from your trace. From this packet, determine how many fields there are in the UDP header. (You shouldn’t look in the textbook! Answer these questions directly from what you observe in the packet trace.) Name these fields. :::info 4 fields 1.source port 2.destination port 3.length 4.checksum :::

R14 R15 R16 R19 P1

Steps Step 1 : 打開瀏覽器（建議用無痕模式) Step 2 : 打開 Wireshark (建議以系統管理員執行)，開始抓 Packet Step 3 : 複製下方網址，貼上網址列 Enter</br> http://gaia.cs.umass.edu/wireshark-labs/INTRO-wireshark-file1.html Step 4 : Filter 輸入 http Step 5 : 找出 HTTP GET Step 6 : 停止抓 Packet Questions 1-1 List 3 different protocols that appear in the protocol column in the unfiltered packet-listing window in step 7 above.

Steps Step 1 : 打開瀏覽器（建議用無痕模式) Step 2 : 打開 Wireshark (建議以系統管理員執行)，開始抓 Packet Step 3 : Filter 輸入 http Step 4 : 複製下方網址，貼上網址列 Enter</br> http://gaia.cs.umass.edu/wireshark-labs/HTTP-wireshark-file1.html Step 5 : 停止抓 Packet Questions 2-1 Is your browser running HTTP version 1.0 or 1.1? What version of HTTP is the server running?

nslookup nslookup nccu.edu.tw nslookup -type=NS nccu.edu.tw nslookup nccu.edu.tw 8.8.4.4 Questions 3-1 Run nslookup to obtain the IP address of a Web server in Asia. What is the IP address of that server? :::info :::

Lab 7-1 What is the IP address of the client? :::info 192.168.1.100 ::: Lab 7-2

Lab 8-1 What is the IP address of your host? What is the IP address of the destination host :::info src: 192.168.1.106 destination: 143.89.12.134 :::

Lab 9-1 What is the 48-bit Ethernet address of your computer? :::info 90:9a:4a:c4:42:2a ::: Lab 9-2 What is the 48-bit destination address in the Ethernet frame? Is this the Ethernet address of gaia.cs.umass.edu? What device has this as its Ethernet address?

Lab 10-1 Are DHCP messages sent over UDP or TCP? Ans: UDP Lab 10-2 Draw a timing datagram illustrating the sequence of the first four-packet Discover/Offer/Request/ACK DHCP exchange between the client and server. For each packet, indicated the source and destination port numbers. Are the port numbers the same as in the example given in this lab assignment? Ans:

4-1 What is the IP address and TCP port number used by your client computer (source) to transfer the file to gaia.cs.umass.edu? ::: info Ans: 192.168.1.106, 63583 ::: 4-2 What is the sequence number of the TCP SYN segment that is used to initiate the TCP connection between the client computer and gaia.cs.umass.edu? What is it in the segment that identifies the segment as a SYN segment? ::: info The sequence number of the TCP SYN segment is 0 since it is used to imitate the TCP connection between the client computer and gaia.cs.umass.edu. According to below figure, in the Flags section, the Syn flag is set to 1 which indicates that this segment is a SYN segment.

Lab 6-1 Select the first ICMP Echo Request message sent by your computer, and expand the Internet Protocol part of the packet in the packet details window. What is the IP address of your computer? Ans: 192.168.0.1 Lab 6-2 Within the IP packet header, what is the value in the upper layer protocol field? Ans: ICMP(1)