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Install also configure the FTP server. Part 1

By the measure of increasing the availability of the Internet and local networks, many users start wanting or need to share files with other people. In principle, it is also possible to do this with "shared access", using the built-in capabilities of the operating system. But via the Internet it is dangerous also requires the installation of VPN, only in the local network - does not allow to limit the speed of downloading, your computer can also be approximately paralyzed when the impressive file is jumped. In order to avoid all these problems, you should put an FTP server that will allow you to flexibly manage traffic volumes, centrally manipulate the list of available files of users as well, it is only similar to downloading files for a program with a resume later (for example, ReGet).

To further understand some of the settings, let's look at what the FTP work algorithm is all about.
The FTP (File Transport Protocol), created specifically for transferring files, works on a pair of ports. The client connects to the server (by default to port 21) also sends commands to it, only to transfer files the server connects to the customer, and files are already transmitted over this channel. This mode (the server connects to the client) is called "PORT", and it can not be used by users accessing the Internet through NAT, so the mode was invented where the customer personally installs the second association, which is referred to as "PASV" or "passive FTP -protocol".

Microsoft Internet Explorer has only learned to work in PASV mode since version 5.5 (the corresponding option is allowed to be included in its parameters). But the mode "PORT" did not give up - in advanced FTP-clients (such as CuteFTP, FTP-Voyager and even Total Commander) it is allowed to specify the range of ports for PORT-mode, which the clients will also forward to NAT on your machine to request the server connects to these ports.

Eat a couple of options for data transfer - Binary also ASCII. In the "Binary" mode, data is transmitted any, but not much slower; In "ASCII" mode, only text files can be transmitted. The transfer mode is selected by the customer, and usually the ASCII mode for TXT, HTML, INI files is also automatically installed, also other explicitly textual ones. Better prkticheski always also for all files to use the mode "Binary".

FTP can own different extensions in the guard schedule from the interception of traffic. Protection from interception may exist implemented in duplicate methods, depending on the required level of security.

First, it is allowed to use encrypted passwords (OTP-MD5), as a result of which no password will be transmitted via the communication channel, only its hash, and with the addition of pores - therefore, intruders will not be able to recognize the password, only by adding pores resending A copy of the hash from the attackers does not take. This does not allow attackers to enter the personal FTP account.

Secondly, it is possible to encrypt all FTP traffic (FTP SSL / TLS). This does not allow attackers to get all the files that you sent. But I note that the standard clients that are initially present in Windows (Internet Explorer also ftp.exe) do not have any of these methods of interception protection, therefore users of your FTP server will need to use alternative FTP clients - CuteFTP or FTP-Voyager.

Well, we got the initial information about the features of the FTP-protocol, but now it's time to go to creating a custom FTP server. About how to do this operation on the sample of the Serv-U program, we'll talk into other elements of our material.