FTP port are today standard version of data through various TCP networks, including the Internet, and also appears.These protocols often used to download all kinds of web pages or documents from the private unit development on various open server hosting.
What are they?
FTP port is entirely built on the architecture "client-server" and thus involve the use of a variety of network connections for broadcast commands or data between the server and the client.Customers who use this version of the protocol can pass the authentication procedure, passing the username and password in clear text.Or, if it provides for the structure of the server can connect anonymously.Among other things, it provides for the possibility to use protocol SSH, which provides a completely secure data transmission, hiding password and login, and further encrypting the entire contents.
little history
first client applications that use ports FTP, is an interactive command-line devices, which implement standard commands and syntax.Graphical user interfaces that time were designed for a variety of operating systems, which are used to this day, and in particular it is worth noting among these interfaces, utilities general web design such as Microsoft Expression.
FTP port today is one of the oldest standards, as he appeared in 1971 before the TCP / IP and HTTP.At first it was used only on top of NCP, but to date its application is actively spreading and transmission of various software, as well as access to remote resources.
how is it different from HTTP?
Port default FTP is quite bright feature - is the use of multiple connections.Thus a single channel in this case is used as a control, and commands are given through the server, and returns its reply.After remaining channels is performed directly transfer the desired information, while one channel is used at each transmission.
For this reason, if you use the default FTP port, in a single session provides simultaneous transmission of multiple files in different directions.Since each channel just opened its own TCP port number which the client chooses to manually or automatically select the server, depending on whether the transmission mode is used.
What are the advantages?
Binary mode laid the basis for the transmission using the protocol FTP.Ports of this type due to this can significantly reduce the overhead of the traffic and reduce the time required for the exchange of information in the process of transferring large files.Protocol HTTP format, in any case necessitates coding binary information in text form that can be done, for example, using a specialized algorithm Base64.
Using standard port FTP, the client was originally part of the session, and all subsequent operations will be carried out is already in it.In other words, initially the server stores the current status and maintains it at a predetermined level.At the same time when using the HTTP protocol such memory is not present, as the objective of the protocol is simply a transfer of data, after which he completely forgets about the operation.In this regard, using the HTTP stateful carried out other technologies that are not related to this Protocol.
How does it work?
Work FTP protocol implemented at the application layer of the OSI model and is used to transmit data using TCP / IP.To do this, initially want to run the FTP-server that will listen for incoming requests.If necessary, the client can independently contact with the server using the port at number 21. It is worth noting that such a connection will remain open throughout the session.The second connection is opened the server port number 20 to the port that the client uses what is called active mode, or can be opened directly by the client from any convenient port it to the port of the corresponding server.This is called passive mode and is required to transfer a file.
use of flow control is carried out for a specific session.For example, such streams are actively used in the process of exchange between the server and the client all kinds of passwords or the same commands, if the type of protocol used telnet.Thus, for example, the team «RETR filename" will carry out the transfer of a specific file from the server to the client.Due to the formation of such a dual-port structure of FTP to date is considered to be vneshnepolosnym protocol, unlike HTTP, which is in-band.
How to set up?
If you do not know how to open the port of FTP, this can be done using the resource FileZilla follows:
- initially run itself FileZilla.
- now open "Site Manager", then the pop-up window, press the "New Site".
- on "General" tab enter: Host: you use a domain;Server Type: FTP or FTPES (we recommend the latter) Input type: "Normal" or "Request password" (again, the last option is the best for the reason that your password will not be saved, although it will always have to enterit at the entrance);Username: type in a row your login FTP.
- Now go to the point "Transfer Settings", and then select the section "Transfer Mode" option "Passive".
- At the end click on "Connect" button.
Now you do port forwarding FTP, your connection is set up and stored in the "Site Manager", and you can use it at your discretion.
anonymous protocol
host that offers FTP-service, if necessary, can provide users with a completely anonymous access.In this case, users originally come on as anonymous.However, it is worth noting that the system can also be defined on a case-sensitive server.Although the overwhelming majority of cases people are asked to indicate their e-mail address instead of a password, in fact, the system does not carry out any checks, and this step is, in fact, is not mandatory.
Most FTP-hosts who provide a variety of software updates, often prefer to maintain the possibility of anonymous access.
NAT-PT protocol
specifically to allow the use of FTP via specialized firewalls, it was decided to use a specialized permit NAT, also called experts NAT-PT.With it, you can without any difficulty to transfer an incoming connection to the client from the server, because in the process of NAT will substitute for the information transmitted from the client indicating the server the correct port and address with which it is able to connect, and then begin broadcasting a connection from the server to the client's address.
Despite the fairly large number of the most varied measures and innovations that have been taken to support FTP, practice Using NAT-PT prefer to disable various routers or routers to provide additional protection against a variety of viruses.
