Analysis of TCP/UDP message structure

Experiment name: TCP/UDP message structure analysis

Lab Topology:

Lab requirements:

1. Configure the R1-R2 interconnection link: 192.168.1.0 Universe 24

2. Configure the telnet password of R2 to access remotely on R1; grab TCP packets and analyze them

3. Run RIP protocol between R1 and R2; grab UDP packets and analyze them

The steps of the experiment:

1. Configure the port IP address of R2 in R1; (and enable packet capture function)

Interface gi0/0/0

Undo shutdown

Ip address 192.168.1.1 255.255.255.0

Interface gi0/0/0

Undo shutdown

Ip address 192.168.1.2 255.255.255.0

2. Configure the telnet of R2 to use the password

User-interface vty 0 4

Authentication-mode password

Hahahehe

3. Configure the routing protocol-RIP; (the same R1/R2 configuration command) rip undo summary version 2 network 192.168.1.0

4. Verification and testing

Catch TCP: telnet 192.168.1.2

Grab UDP: after configuring RIP, you can grab it at any time. Because RIP is a periodic package.

5. Save the configuration

Save

Summary of the experiment:

-1. Ethernet head mechanism

0. IP header structure

1. TCP structure

2. UDP structure

3. The port number of RIP is udp 520, and the packet is sent by broadcast (255.255.255.255)

4. The port of Telnet is tcp 23.

5. When an application is represented by a port, the port generally represents the target port.

At this point, the corresponding source ports are all "random high ports"