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Editor to share with you what linux operation and maintenance ftp server functions, I believe most people do not know much, so share this article for your reference, I hope you will learn a lot after reading this article, let's go to know it!

As one of the oldest protocols, ftp is not widely used at present. It is mainly used for file transfer between server and client. Ftp protocol uses plaintext transmission protocol, all of which have certain security risks. There is a vsftpd software on the linux system. Although this software does not have many functions, it focuses on security. It is recommended that you use this software as a ftp file transfer server. In addition, pure-ftpd is also commonly used.

Brief introduction of ftp Featur

Ftp has the following main functions:

Allows files to be transferred and managed between the client and the server. This is the most important function and the core of ftp.

Different levels of user identities. Ftp has three different identities by default: entity user, guest, and anonymous user (anonymous). The permissions corresponding to these three identities are different, and entity users have the largest rights, and anonymous users may only have the right to browse files or do not have any permissions.

A directory that restricts user activity. This is also the core function of ftp to prevent other directory files on your server from being disgusting and corrupted. When you log in with your account password, you can only move under the account's home directory, and you can't enter other directories.

Ftp transmission mode

Compared with ssh, ftp is more complex. Unlike ssh services, which only need to open one port, ftp services require two ports. The uses of these two ports are different. Generally, the server uses port 21 as the command channel and port 20 or other random ports as the data transmission channel. According to the different ways of establishing data channels, it is divided into two modes:

Active mode: the server initiates a connection to the client. In active mode, 20 ports are used by default for data transmission.

Passive mode: the client initiates a connection to the server. The ports used in this mode are random and can be customized.

In the next article, I will explain the active mode and passive mode of ftp in detail. We often encounter such a problem, why can not connect to the ftp server, clearly account password and ip input are normal, but can not connect? When we understand the two transmission modes of ftp, this problem can be easily solved.

The above is all the contents of the article "what are the ftp server functions of linux operation and maintenance". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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