1. Experimental principle
1. FTP overview
FTP is the English abbreviation of File Transfer Protocol, while the Chinese abbreviation is "文传protocol". Used for two-way transmission of control files on the Internet. At the same time, it is also an application (Application). There are different FTP applications based on different operating systems, and all these applications follow the same protocol to transfer files. In the use of FTP, users often encounter two concepts: "Download" and "Upload". "Download" a file is to copy a file from a remote host to your own computer; "upload" a file is to copy a file from your computer to the remote host. In Internet language, users can upload (download) files to (from) a remote host through a client program.
2. FTP features
Two TCP connections are used:
1. Control connection: command interaction, FTP server listens on port 21
2. Data connection: transfer data
3. FTP connection mode
1. Passive mode (PASV)
server listens, client initiates Connection
2. Active mode (PORT)
client listening, the server initiates the connection
4. FTP transfer process
2. Experimental configuration
1. Experimental topology diagram
2. Experimental steps
1. Configure the IP address of the client;
2. Configure the IP address of the
FTP server ; 3. Configure the file root directory of the FTP server;
4. Test the connectivity between the client and the server;
5 .Start the FTP server;
6. The client accesses the FTP server;
7. Start wireshark for group capture, and simultaneously upload and download files.
3. Experimental results
The server sends its own related information to the client. The following status code 220 indicates that the service is ready.
227: means entering passive mode
125: means opening data
226: means ending data connection
200: command executed successfully