One. Test and modify the IP address of the communication
Ping own ip 192.168.43.177
First, the application layer
1, WWW packet capture analysis
Select the captured data in an http message, open it and find the URL, copy the URL and open it in your browser.
2, YY live packet capture
Wireshark open software, open YY live website, select udp crawl
Second, the transport layer
1, TCP link established
(1) The first handshake
Source port number: 55720
Destination port number: 443
Byte length header: 32 bytes
Sync bit: SYN = 1
Selection number seq = 0
(2) The second handshake
Source port number: 55718
Destination port number: 443
Byte length header: 32 bytes
Sync bit: SYN = 1
Send an acknowledgment: ACK = 1
No acknowledgment: ACK = 0 + 1 = 1
Selection number seq = 0
(3) third handshake
Source port number: 55718
Destination port number: 443
Header bytes: 20 bytes
Sync bit: SYN = 1
Send an acknowledgment: ACK = 1
No acknowledgment: ACK = 0 + 1 = 1
2, TCP link release
(1) The first handshake
FIN = 1, selection number: seq = 223, waiting for an acknowledgment
(2) The second handshake
ACK = 1, ack = 223 + 1 = 224, seq = 812, TCP link is disabled
(3) third handshake
After FIN = 1, seq = 812, ack = 224, ACK = 1, the client receives a connection release segment, must send a confirmation
(4) Fourth handshake
ACK = 1, ACK = 813, SEQ = 224
3, UDP protocol
Enter udp packet capture filtering software, select a udp packet
Source port Source port: 53
Destination port Destination port: 55895
The Length: 98
Checksum checksum: 0x1cb2
Third, the network layer
1, IP packet analysis
Header length is: 20 bytes
IP packet version number is: IPV4
Datagram length: 40
Identifier: 0x0ecc
Flag: 0x4000
Life: 128
Upper-layer protocols: TCP
Header checksum: 0xb689
The source IP address of 192.168.43.177
Destination IP address: 120.92.208.196
2, ARP protocol analysis
Broadcast request unicast response
Request: the source address mac: 88: 6a: b1: 11: a4: 4e
The purpose mac address: 14: ab: c5: a8: f5: b6
Source IP address: 192.168.43.1
Destination IP Address: 192.168.43.177
Fourth, the data link layer
Data link layer to the physical layer based network to provide reliable service. It defines the physical address and the primary physical destination address.
1, MAC address analysis:
Source Address: 08: 35: 71: eb: 09: 49
Frame Number: 135
Capture length: 481 bytes
V. summary
In fact, this time the feeling is especially rewarding job, do not always feel, but also to help each other through group finished, cut the map with a lot of Zhang, also drew a full two-page paper, released four connected时候蒙圈了，感觉绕不过弯，花费了很长时间。Later, writing to me in the past and write a panel discussion finally figured it out on paper. Modify the IP address, they also flawed, then suddenly realized this side DNS, you can be connected to the network. Overall this assignment for me and my team a big harvest,