How to configure FTP ports? What are FTP-ports?

FTP ports are today the standard version of data transmission through various TCP networks, including the Internet. These protocols are often used to download all kinds of network pages or documents from a private development device to various open hosting servers.

What are they?

FTP ports are built entirely on the client-server architecture and at the same time provide for the use of a wide variety of network connections for the transmission of commands or information between the server and the client. Users who use this protocol option can pass authentication procedure, passing the password and login in clear text. Alternatively, if this provides a server structure, they can be connected anonymously. Among other things, it is also possible to use the SSH protocol, which provides absolutely safe data transmission, hiding the password and login, and also optionally encrypting all the content.

A bit of history

The first client applications using FTP ports were interactive command line devices that implement syntax and standard commands. Graphical user interfaces have since been developed for the many operating systems that are used to date, and in particular it is worth noting among such interfaces common web design utilities, such as Microsoft Expression.

FTP ports are one of the oldest standards these days, because it appeared in 1971 before TCP / IP and HTTP. At first, it was used exclusively on top of NCP, but today its use is actively spreading both for the transfer of various software, as well as access to remote resources.

What are its differences from HTTP?

The default FTP port has a rather bright feature - it is the use of multiple connections. In this case, one channel in this case is used as a manager, and through it commands are given to the server, and responses are returned from it. Through the other channels, the transmission of the necessary information is carried out directly, with one channel being used for each transmission.

It is for this reason, if you use the default FTP port, within the same session, simultaneous transmission of several files in different directions is provided. Since each channel simply opens its own TCP port, which is manually selected by the client or automatically chooses the server, depending on which transmission mode is applied.

What are the advantages?

Binary mode is the basis of the transfer using the FTP protocol. Ports of this type allow you to significantly reduce the overhead of traffic, as well as reduce the time it takes to exchange information during the transfer of large files. The HTTP protocol in any case necessitates the encoding of binary information in a text form, which can be done, for example, using the specialized algorithm Base64.

Using the standard FTP port, the client initially enters the session, and all subsequent operations will already be conducted in it. In other words, the server initially remembers the current state and maintains it at a certain level. At the same time, when using the HTTP protocol such memory is not present, since the task of this protocol is simply data transfer, after which it completely forgets about the operation. In this connection, when using HTTP protocols, state storage is performed by other technologies that do not relate to this protocol.

How it works?

The FTP protocol is implemented at the application layer of the OSI model and is used to transfer data using TCP / IP. To do this, you must initially start an FTP server that will wait for incoming requests. If necessary, the client will be able to contact the server independently using the port number 21. It is worth noting that this connection will remain open during this session. The second connection is opened by the server from port number 20 to the port that the client uses, which is called the active mode, or it can be opened directly by the client from any convenient port to the port of the corresponding server. This is called passive mode and is required for file transfer.

Using the control flow is done to work with a specific session. For example, such threads are actively used in the process of exchange between the server and the client with all possible passwords or commands, if a protocol of the telnet type is used. Thus, for example, the command "RETR filename" will transfer a specific file to the client from the server. Due to the formation of such a two-port structure, FTP is today considered to be a foreign-band protocol, in contrast to HTTP, which remains in-band.

How to setup?

If you do not know how to open the FTP port , you can do this using the FileZilla resource as follows:

1. Initially, you run FileZilla itself.
2. Now open the "Site Manager", then click the "New Site" button in the pop-up window.
3. On the General tab, enter: Host: the domain you use; Server type: FTP or FTPES (it is recommended to use the latter one), Login type: "Normal" or "Request password" (again, the latter option is optimal for the reason that your password will not be saved, Its at the entrance); User name: enter your FTP login in this line.
4. Now go to "Transfer settings", then select "Passive" in the "Transfer mode" section.
5. At the end click on the "Connect" button.

Now you have made FTP port forwarding , your connection is configured and stored in the "Site Manager", and you can use it at your discretion.

Anonymous Protocol

A host with an FTP service, if necessary, can provide users with anonymous access. In this case, initially users enter the system as anonymous. However, it should be noted that the system can also be case sensitive on certain servers. Although in the majority of cases users are asked to specify their e-mail address instead of the password, in reality the system does not conduct any verification, and this step, in fact, is not mandatory.

Most FTP hosts that provide various software updates often prefer to maintain anonymous access.

NAT-PT protocol

Especially in order to make it possible to use FTP through specialized firewalls, it was decided to use a specialized NAT solution, also called NAT-PT. With it, you can easily transfer incoming connections to the client from the server, because in the process NAT can replace the transmitted information from the client, indicating the server the correct port and the address with which it can connect, and then it will start broadcasting the connection from the server to the client address.

Despite the large number of various measures and innovations that have been taken to provide FTP support, in practice the use of the NAT-PT function is preferable to be disabled in various routers or routers in order to provide additional protection against various viruses.