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This article mainly introduces how to monitor the ftp server in the FTP server, upload files to the ftp server, ftp file monitoring, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let Xiaobian take you to understand.

Page 1: the role of the FTP server

FTP servers (File Transfer Protocol Server) are computers that provide file storage and access services on the Internet, and they provide services in accordance with the FTP protocol. FTP server is often used for file sharing and transfer, which is an indispensable part of the Internet field.

The role of FTP server

The FTP server is created to solve the problem of file transfer obstacles. So what role does the FTP server play in between?

In the initial period of the Internet, it is a very tricky thing to transfer files on the Internet. Not only do different users use different terminals, such as personal computers, Mac, workstations, mainframes, etc., but also operating systems are very different. Systems such as Windows, Unix, Dos or MacOS operate in very different ways, and there are great restrictions on transmission and sharing.

The FTP protocol includes various clients and FTP servers.

In order to eliminate this communication problem, Internet workers need to establish a unified transport protocol, which is the FTP protocol. The two major components of FTP protocol are FTP server and FTP client. The FTP server acts as a transit station and storage center to transfer, save and distribute files to various clients.

Upload and download files between the two

Most of the files stored in the FTP server are copied from the user's client program using the FTP protocol to the FTP server program on the remote host for storage, this process is called upload (upload, also known as upload); similarly, the process for users to copy files from the FTP server and transfer them to their terminals is download. The upload and download process is the most common operation that we can use.

Page 2: connection to the FTP server

Connection to the FTP server

Because the FTP server undertakes the important task of file storage and dissemination, its connection with users also has triple restrictions.

Before using the FTP server, you must log in to obtain a remote connection before the user can access the required files. There are usually two ways for users to take away the files they want, one is Standard, that is, PORT, which is an active way to connect with the server, and the other is Passive, that is, PASV, which is a passive way to connect with the server.

FTP protocol connection system

If you want to take the file you want, you have to go through the triple door. The first important door is the user login, that is, the user ID and password, otherwise you will not be able to connect to the FTP server to get the file. This door is the first door, but the problem is that it seriously limits the openness of the Internet, so now the importance of this door has been greatly reduced.

The last two doors are the ports of the FTP server. The second door is the TCP port 21 of the FTP server. After the FTP client has established a connection with this port, it can send commands through this channel, and customers can send commands in this channel when they receive data.

Establish a connection in Port mode

The third door is a little more complicated. In the past, the above commands were usually Port commands, and after they were transferred to the FTP server, the server would connect to the customer-specified port from its own TCP20 data port to copy and transfer files. In this way, the FTP server and the client need to establish a new connection to transfer data.

Because the security of this new connection is difficult to guarantee, there is another form of the third door of the FTP server, that is, the commands sent by users no longer use Port commands, but Pasv commands. After receiving this command, the FTP server will open a high-end random port whose port number is greater than 1024, and then inform the client to transmit data requests at this port, and finish the data transmission directly at this port, while the FTP server does not need to establish a new connection with the client.

Page 3: anonymity mechanism of FTP server

Anonymity Mechanism of FTP Server

And some friends will wonder, if I download software on the Internet, I did not provide him with any login information, user ID and password ah? That's because the FTP server also has an anonymous FTP mechanism.

As mentioned earlier, the existence of the first door hinders the openness of the Internet, so in order to increase the convenience of information exchange, an anonymous FTP mechanism is created. In this mechanism, the system administrator establishes a special ID,anonymous. All people who have access to the Internet can use this id, which is equivalent to providing a key hanging on the door, and the user's password can be any string, so there will be no obstacles to login.

Anonymous FTP server has a unified user name

However, the anonymous FTP mechanism does not allow all files to be shared and made public. In other words, when remote hosts provide anonymous FTP services, part of the directories are often open, allowing users to access them anonymously, while most directories are hidden.

Another problem comes one after another. Because FTP servers have access functions, there are too many Trojans and files with viruses on the Internet. if these files are also put in, it will be easy to spread, won't they? The solution is simple: most anonymous FTP servers are fetched and not saved.

Even if it is able to provide storage services, users can put into a special shared space, only save but not take. When the system administrator collates these files regularly, the dangerous files will be deleted and discarded directly, and the security files can be sorted out and classified for storage or public use.

In this case, anonymous login is not allowed.

In theory, anonymous FTP has the opportunity to become the world's largest information base, because the information and documents are constantly collated, open, grown and optimized, can be used almost unclosed, all topics are likely to be covered, and they are all free of charge. This is also the most commonly used method of software release and download today.

To some extent, the development of the Internet is due to the use of procedures that provide standard services through standard agreements, which provides a basis for communication and makes the flow of information valuable. And the FTP server is undoubtedly the biggest help, it has injected vigorous vitality into the Internet.

If you want to monitor the file access operation of the FTP server, you can deploy the general trend to the FTP file server monitoring software (download address: http://www.grabsun.com/ftpjk.html). After installation on the FTP server, you can fully monitor the FTP server file access log, record and modify FTP server files, delete ftp server files, download ftp server files and upload ftp server files. Thus, it is convenient for the administrator to grasp the use of ftp server files in real time and protect the security of FTP server files. As shown in the following figure:

In a word, the construction of FTP file server and its file management is a relatively complex and meticulous work. Based on a comprehensive grasp of the relevant configuration, and with the corresponding FTP file monitoring software, we can maximize the security of FTP server files.

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