1. Application layer: File Transfer Protocol FTP
Source of notes:
Teacher of Lake University of Science and Technology: Overview of the Application Layer
Teacher at Lake University of Science and Technology: File Transfer Protocol FTP
Disclaimer: The study notes are from a teacher at HuUST and are for study reference only.
Transferring files from one computer to another computer that may be far away over the network is a basic network application, namely file transfer.
FTP provides interactive access, allowing customers to specify the type and format of files (such as specifying whether to use ASCI codes), and allowing files to have access rights (such as users accessing files must be authorized and enter a valid password) FTP shields the details of each computer system
, therefore suitable forTransfer files between any computer in a heterogeneous network
Upload files to FTP server
Download files from FTP server
Common uses of FTP
1. Transfer files between computers, especially batch transfer files
2. Let website designers upload a large number of files that constitute website content to the web server in batches
How FTP works
Active mode (when establishing a data channel, the FTP server actively connects to the FTP client)
control connectionRemains open during the entire session and is used to transmit FTP related control commands
Data ConnectionsUsed for file transfer, it is established every time a file is transferred and closed after the transfer.
Passive mode (when establishing a data channel, the FTP server passively waits for the FTP client's connection)
