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FTP stands for File Transfer Protocol. Such as the definition of their own FTP, FTP has a function to transfer files between computers / devices connected to a TCP / IP network (LAN / Internet). FTP (File Transfer Protocol) is an Internet protocol that runs on the application layer which is a standard for transferring files (files) between the computer machines in an internetwork. This protocol is still used to this day to make downloading (downloading) and penggugahan (upload) files between your computer and the FTP client FTP server. An FTP server is accessed by using a Universal Resource Identifier (URI) using ftp://namaserver format. FTP client can contact the FTP server by opening a URI tersebut.Mungkin some of my friends have heard or may already know about FTP.

How FTP Works 

1. After learning a little about what it FTP and also basic functions, I will write here the workings of FTP in general.
2. Standard FTP port is 21 (on the server).
3. On the server side, ftp server waiting for incoming connection on port 21 (the default).
4. FTP client attempts to connect to the ftp server (daemon) with the user entering his or her password (usually FTP does have a separate authentication.)
5. FTP server checks the whether the user and his password is valid, if valid it will continue to the next step, if not valid then be asked to enter a user / password to another several times, if it remains invalid then the connection will be disconnected.
6. Once the user is validated then ftp client can men-download/men-upload or delete any files contained in the server, depending on user access.

Before making connections, TCP port number 21 on the server will "listen" connection attempt from an FTP client and then be used as a control port (control port) to

make a connection between client and server,

to allow the client to send a command to the FTP server and also

returns the server response to the command. Once the control connection has been made, then the server will start to open the TCP port number 20 to establish a new connection to the client to transfer the actual data that is being exchanged during the download and penggugahan.

FTP uses only standard authentication methods, namely using the username and password are sent in unencrypted form. Registered users can use the username and password to access, download, and upload files he wants. Generally, registered users have full access to multiple directories, so that they can create files, create directories, and even delete files. Non-registered users may also be able to login using anonymous methods, namely by using the anonymous user name and password are filled in using the e-mail address.