FTP - File Transfer Protocol Explained

File Transfer Protocol (FTP) is a protocol that is part of the TCP/IP suite. It is the standard for transferring large amounts of data from server to server and from servers to clients. There is a very good chance that you have downloaded files from FTP sites many times, though it may have seemed you were only downloading from a website. FTP allows you to transfer files over a variety of hosts with different operating systems and file systems. There are so many FTP servers on the Internet, some are private with secure logon names, other ones are public with anonymous logins.

This paper will give a very brief outline of how the FTP Protocol functions and give the basic commands used during an FTP session. Keep in mind that these commands are generally automatic and are executed by either an FTP Client application, or done via your web browser. Though these methods are generally quicker than manually connecting to an FTP, it doesn't mean we should ignore the background behind how the technology works.

The FTP Protocol uses two connections to transfer a file. Each of these connections is quite a bit different, but work in conjunction with each other. The first connection is the Control Connection, which as the name implies controls the connection in regards to initiating the data streams and executing the commands. The second type of connection is the Data Connection, this connection is the actual connection that passes the files back and forth between the client and server.

Control Connection:
The control connection starts in a normal client / server manner. The client does an active open connection to port 21 of the FTP server to establish the control connection. The server is listening on port 21 for any active queries. Please keep in mind that though the primary FTP port is designated as porn 21, many servers, especially private ones are running on non-standard ports. The control connection as I mentioned early is the connection that allows you to pass commands between the client and server. Commands that must be sent are ones like LIST, STOR, and RETR. Once you enter a command on the control connection, you initiate the data connection.

Data Connection:
The data connection is spawned each time a file is moved between the client and server. The Control connection initiates the transfer with the PORT command, this tells the server to open an active connection to the clients passive port. The port command is typically the IP address followed by a 16 bit port number. The PORT command is issued in the following fashion:

PORT 24,82,116,92,4,150

That command should spawn a response of: 200 PORT Command Successful

After the PORT command has been initiated and is successful the next command in the data connection will be issued from the control connection. As I mentioned before this is typically a LIST, RERT or STOR. I will outline the basic FTP commands below for reference.

FTP Commands (Basic):
ABOR - Abort command and any data transfers
LIST - List the directory contents
PASS password - Used during authentication of login
USER username - Used during authentication of login
QUIT - Logoff / Quit session
RETR filename - Retrieve file from server STOR filename - Send a file to the server
SYST - Show System information
TYPE - Set the type of data, for instance ASCII
PORT - n1,n2,n3,n4,n5,n6 ( 1-4 = ip address, 5-6 port data)
HELP - Will give you additional available commands and more information

Reply Codes:
Reply codes are simply confirmations of things happening. One example of a reply code was went we got "200 PORT Command Successful" there are a handful of other reply codes, though generally the main ones are as follows.

125: Data Connection Open Start Transfer
200: Command OK
221: Goodbye / Terminate Connection
252: Write Error
331: Username OK, Enter Password
425: Can't Open Data Connection
500: Syntax Error on Command
501: Syntax Error on Arguments

Client Applications:
There are many different clients for FTP, and really it's up to personal taste in the end. A couple of the major ones are CuteFTP and FlashFXP. Personally I use FlashFXP when I'm in the Windows Environment. Just go to a freeware website or search on the search engines for a FTP Client and try a few out!

Summary of FTP:
The File Transfer Protocol is a wonderful and useful standard that has helped move data around the world safely and reliably for years. Everyone uses it from uploading their website to their web server, backing up their data to an off-site location, sharing their pictures with friends, or disseminating large data files for scientific research!

For even more information on the FTP, check out RFC 959.

Ken Dennis
http://kendennis-rss.homeip.net/

Wood Dale Chicago prom limo .. Lockport Chicago limo O’Hare
In The News:

Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents
Internet browsers are useful, but they can be dangerous. Clicking on malicious links can direct you to dangerous websites that steal information or infect your device.
Apple's latest iOS update introduces advanced artificial intelligence capabilities, which may be capturing and analyzing sensitive information.
Breach site confirmed 56,904,909 Hot Topic users' data leaked online. Tech expert Kurt “CyberGuy" Knutsson says the company's silence makes matters even worse.
Tech expert Kurt “CyberGuy" Knutsson discusses how an innovative Easy-Way kit turns standard strollers electric, simplifying navigation for parents.
Tech expert Kurt “CyberGuy" Knutsson talks about T-Mobile being hacked in broad cyberattack on global phone and internet companies.
Tech expert Kurt “CyberGuy" Knutsson shows you how to add, customize and manage widgets for quick access to apps and info from your iPhone home screen.
Wrong Google searches can not only compromise your device and personal data. They can also bring law enforcement to your doorstep. Hackers are targeting Google searches.
China's Shanghai Kepler Robotics has developed a new humanoid robot that can carry up to 35 pounds per hand for commercial applications across various industries
Checking your hearing has gotten easier with the new hearing test feature in AirPods Pro 2. You can take reliable hearing tests using your iPhone or iPad.
Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.
Kurt "CyberGuy" Knutsson explains how a VPN — virtual private network — works and how running it can slow down the operation of your device.
The WalkON Suit F1, an exoskeleton developed to help people with disabilities, can actually walk over to a person in a wheelchair, solving a major problem.
ClickFix, a new scam targeting computer users, is on the rise in the U.S. The scam prompts its targets to click on a link to fix a problem.
Skydweller is the world's largest unmanned solar-powered aircraft that can stay airborne for weeks, and even months, without refueling.
The U.S. government said it is investigating after People's Republic of China hackers targeted commercial telecommunications service providers in the U.S.
Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.
Scammers are using increasingly sophisticated ways to lure unsuspecting victims, and some are impersonating an email help desk or support team.
You can unsend or edit your iMessages with the latest iOS updates. Kurt the CyberGuy explains how you can save yourself some potential embarrassment.
Kurt “CyberGuy" Knutsson says there’s been a rise in cybercriminal services using hacked police and government emails to send subpoenas and data requests to U.S. companies.
Kurt “CyberGuy" Knutsson discusses how Axiom Space and luxury designer Prada are collaborating on NASA's Artemis III spacesuit design.
Voice assistants may cause confusion across devices. Tech expert Kurt “CyberGuy" Knutsson offers some solutions to fix it.
Shameless scammers trick veterans into giving personal info or cash. Tech expert Kurt “CyberGuy" Knutsson explores five common scams.
Tech expert Kurt “CyberGuy" Knutsson helps you honor our heroes with these powerful podcasts, audiobooks and documentaries this Veterans Day.

Cisco Certification: The Most Important Cisco Study Youll Ever Do

All of us are familiar with the pyramids of Egypt.... Read More

What?s the Difference Between Plasma TVs and LCD TVs?

Plasma and LCD TVs are the latest trend in home... Read More

Do Higher Digital Camera Prices Mean Better Cameras?

Understanding digital camera prices makes finding the best camera value... Read More

What Are You Looking For In A Cheap MP3 Player?

Are you stymied by the vast offerings in cheap mp3... Read More

Bluetooth Technology: Tips for Buying Headsets or Headphones

The technological horizon has always got something new to offer,... Read More

10 Tips to SPEED Up Your PC

1. Let your PC boot up completely before opening any... Read More

How To Remove One Operating System from a Dual Boot Windows XP Computer

In Windows Xp, you can install two operating systems on... Read More

4 Computer Money-saving Tips

Tip #1 -- Rebates: A rebate is not always a... Read More

Tips For Getting Technical Support Help Online

Sometimes your PC will start acting strange for no apparent... Read More

Computer Viruses are Bad Luck

OK, so you caught a computer virus and your system... Read More

A Tale of Two Regeds

Tech support tells me to type 'regedt32' as opposed to... Read More

404 Error Pages: What Are They And How Do You Create One?

We've all seen them, you've been browsing a website and... Read More

Dynamite Comes in Small Packages - Tiny Personal Audio MP3 Players Pack Powerful Music Enjoyment

MP3 players are Hot! Playing music has come a long... Read More

Bios Term

BIOS - Basic Input Output SystemThe central processing unit of... Read More

SOBIG.F Virus Promises Ill Be Back

On 21 August 2003 Symantec Security Response upgraded the W32.SOBIG.F... Read More

If You are the Only User on Your Windows XP Computer, Do You Think One User Account Is Enough?

I am going to assume that you are running windows... Read More

EDTV vs HDTV

Confused by EDTV vs HDTV? We don't blame you. The... Read More

Best PC Pocket GPS

Stop Getting LostOne of the greatest uses for a pocket... Read More

Refurbished Computers on the Internet

What is a Refurbished Computer?Refurbished Computers. Remanufactured Computers. Reconditioned Computers.... Read More

Lives With Games Tradition and Industry

The United States Of America citizen feels that games is... Read More

5 Steps to Remove Spyware for Free

Have you ever tried to remove Spyware off your PC... Read More

Get Ahead When You Build Your Own Computer

If you've been kicking around the idea of building your... Read More

Is DVD Storage An Attractive Alternative For Your Computer Backup?

If you have a computer for home use or for... Read More

How Does My PC Get Hot

There are many sources of heat that can raise the... Read More

The Help Desk

When you think of a help desk, what do you... Read More

Antigo wedding limo ..