To store data remotely, connecting between the local and remote machines is necessary. This connection is established via a protocol called FTP.
What Is File Transfer Protocol (FTP)?
FTP stands for File Transfer Protocol. It is a service that allows you to upload or download files from remote machines. It does not matter if the remote machine is your web server or your friend’s computer; FTP will allow you to manage files and folders on it.
How File Transfer Protocol (FTP) Works
Protocol Version Identification
The FTP protocol starts with a command-line negotiation. The client software on the local machine will send the server the protocol version number it wants to use, along with a port number which it wants to use.
Server’s Response
Next, the server responds by telling the client what protocol version it supports along with its port number. If both versions match, then there is no need to match the port numbers. However, if they do not match, they must be in the match for communication to proceed.
Establishing the FTP connection
After the versions are decided upon, the client software will send a command to begin establishing the TCP connection to the server. The process of doing this is called opening a socket. Once that is done, then all data can be transmitted through that socket.
Sending Commands
The client software now sends commands to the server, which it expects to receive in response (similar to sending XML file requests). The commands are sent in a form that carries with it what information is expected in return. It is called an Expect packet.
Processing Responses
When the client receives a response from the server, the data is sent using the appropriate command to indicate what information has been received. It is called an Expect block.
Closing connections
Finally, when both client and server are done sending/receiving data, they close their respective connections by calling their Close Request() callback functions.
Advantages of using FTP
Reliable
When FTP is used to transfer large amounts of data, there is always a chance of the connection breaking. In such cases, FTP will immediately attempt to re-establish the connection as long as it has not been idle for more than 5 minutes. It ensures that data transfers are continuous and reliable.
Security For Data Being Transferred
FTP uses a challenge handshake mechanism where the client sends a challenge request and responds with a reply based on a shared secret known only to the server and client. This mechanism is used to authenticate the client and to allow access to the server. For this reason, it is important to make sure that both machine and user names are accurately known and entered correctly.
File transfer progress monitoring
The most notable advantage of using FTP for file transfers is that it provides information about the progress of the FTP transfer, such as how much data has been sent/received and the time taken. One can use the information to determine when a connection should be closed or process certain files before others. Companies such as Egnyte, enables sensitive files to be transferred securely.
Disadvantages
Slow speed
One of the biggest disadvantages of using FTP is that it is slow. The main reason for this is that it uses a TCP connection, a local communication mechanism, and does not take advantage of the WAN network’s potential for high-speed transfer.
Large files
It is generally not efficient to use FTP for huge files. FTP’s main limitation is that it can only transfer a file of 10 gigabytes or less.
Unsecure with Telnet
Using Telnet instead of FTP to connect to a server can be considered insecure since Telnet does not have the “challenge handshake” authentication mechanism. However, it should be in the notice that this is not usually an issue as most systems do not permit user access without using a username and password.
No authentication for file access
Since FTP only provides a mechanism to authenticate clients connecting to a server, it does not ensure that no one but the authorized user can read or write data on the server. It can be rectified using conventional security protocols, which use public/private keys to encrypt and decrypt users’ data.
File Transfer Protocol is an effective, easy to implement, and reliable mechanism for transferring files between two computers. It has some notable disadvantages, such as speed and security; however, one can overcome the appropriate use of other more secure protocols. Ideally, FTP should be in use for large files where speed is not a key factor or security is paramount.
