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Third experiment: using Packet Tracer analysis TCP connection establishment
- Name: Wei Wentao
- Student ID: 201821121048
- Class: calculated 1812
1 Purpose
- Using different network router
- Use the command line router
- By grabbing HTTP packets, TCP connection establishment process analysis
2 Experimental content
Use Packet Tracer, properly configure the network parameters, by crawling HTTP packets, analyzes the TCP connection establishment procedure.
- Establish a network topology
- Configuration parameters
- Ethereal
- Analysis of the data packet
3. The test report
3.1 Establish a network topology
FIG network topology is as follows
3.2 Configuration Parameters
- IP address of the client is
192.168.1.48 - IP address of the server is
192.168.2.48
router:
Router> enable # to enter the privileged EXEC mode
Router # configure terminal # enter the global configuration mode
Router (config) #hostname R # Name configured router R
Configuring G0 / 0 Interface:
R(config)#interface G0/0
R(config-if)#ip address 192.168.1.80 255.255.255.0
R (config-if) #no shutdown # activate the interface
Configuring routing algorithm:
Verify configuration parameters:
3.3 capture, analyze TCP connection establishment
Ethereal start:
Caught in the package:
(1) Draw a schematic view of a TCP connection
As shown below:
(2) Change in number and acknowledgment number
The first handshake: a client first creates a transmission control module, a TCP connection is established; in this case the header sync bit SYN = 1, while selecting an initial sequence number seq = x
Second handshake: confirmation packet sent by the server to the client, the SYN and ACK bits are set to 1-bit acknowledgment number is ack = x + 1, and also choose an initial sequence number for itself seq = y
Third handshake: the client subject to confirmation message, but also to respond to the server; ACK set to 1, confirm the number ack = y + 1, and their number seq = x + 1
(3) Q & A: Why we need a third connection establishment handshake
In order to prevent the connection request has failed segment suddenly reached the server, and thus avoid an error resulting from continuous data transmission network failure.
- Name: Wei Wentao
- Student ID: 201821121048
- Class: calculated 1812
1 Purpose
- Using different network router
- Use the command line router
- By grabbing HTTP packets, TCP connection establishment process analysis
2 Experimental content
Use Packet Tracer, properly configure the network parameters, by crawling HTTP packets, analyzes the TCP connection establishment procedure.
- Establish a network topology
- Configuration parameters
- Ethereal
- Analysis of the data packet
3. The test report
3.1 Establish a network topology
FIG network topology is as follows
3.2 Configuration Parameters
- IP address of the client is
192.168.1.48 - IP address of the server is
192.168.2.48
router:
Router> enable # to enter the privileged EXEC mode
Router # configure terminal # enter the global configuration mode
Router (config) #hostname R # Name configured router R
Configuring G0 / 0 Interface:
R(config)#interface G0/0
R(config-if)#ip address 192.168.1.80 255.255.255.0
R (config-if) #no shutdown # activate the interface
Configuring routing algorithm:
Verify configuration parameters:
3.3 capture, analyze TCP connection establishment
Ethereal start:
Caught in the package:
(1) Draw a schematic view of a TCP connection
As shown below:
(2) Change in number and acknowledgment number
The first handshake: a client first creates a transmission control module, a TCP connection is established; in this case the header sync bit SYN = 1, while selecting an initial sequence number seq = x
Second handshake: confirmation packet sent by the server to the client, the SYN and ACK bits are set to 1-bit acknowledgment number is ack = x + 1, and also choose an initial sequence number for itself seq = y
Third handshake: the client subject to confirmation message, but also to respond to the server; ACK set to 1, confirm the number ack = y + 1, and their number seq = x + 1
(3) Q & A: Why we need a third connection establishment handshake