File Transfer Protocol (FTP) allows users to transfer files between a client and server computer. FTP uses two TCP connections - port 21 for control commands and a separate high-numbered port for data transfer. To connect, an FTP client enters the server address, username, password, and port 21. FTP has security issues as it transmits passwords and files in plain text, allowing interception, and does not strongly authenticate users.

1. File Transport Protocol

2. Content
1- definition
•2-Connecting to an FTP Server
3-The FTP model
4-Problems with FTP

3. File transport protocol (TFP)
Standard Network Protocol to transfer files from a
client computer to a server computer is "uploading"
and from a server to a client is "downloading".
access an FTP server
users must be able to connect to the Internet or
an intranet (via a modem or local area network)
with an FTP client program.

4. FTP Client (request)
Software deal with server through graphical user
interface such ( FileZilla - Fire FTP – Dreamweaver )
You can work with FTP using a simple command-line
interface, such as The DOS console in windows
and Terminal In Linux And Mac OS

5. •Connecting to an FTP Server
To use FTP, you will need FTP client software to connect
FTP server. You also need to know the server address, the
username, and a password and port number. The basic
information you need in order to log in successfully follows
definitionLogin example
This is the site address of the FTP server you’re connecting tohost
username used for logging into FTPlogin
PASS is the passwordPASS
PORT is the COMMAND port number you are using to
connect to the server. The most common port number is port 21
port

6. •Connecting to an FTP Server
1-Download FileZilla
2-Open FileZilla
3-Enter your FTP server's information
host – username – password - port
4-Click Quickconnect
5-Review the FTP server's contents

7. 1
2
3
4 5

8. Anonymous FTP
•Various public servers allow anonymous login. Users
can log in to servers without an account to download
files. Uploading is not allowed for anonymous login.
Take note that your IP address is tracked even though
it is an anonymous session
•Some more commands
Get Also called “Download”. Copy files from the FTP site
to the FTP client’s system.
put Also called “Upload”. Copy files from the client’s
system to the FTP site

9. •During an FTP connection, two transmission
channels are open
A channel for commands (port 21)
(control channel) , a control channel that stays open for the
entire session
A channel for data (port 20)
, data channel that opens and closes to transfer data such
as folder listings and files to or from the server as
requested by the client.

10. Why does FTP have two port number (20 – 21) ?
FTP uses two TCP connections for communication.
One to pass control information, and is not used to
send files on port 21, only control information.
And the other, a data connection on port 20 to send the
data files between the client and the server. The
connection has to be established before the files can
actually be sent across.

11. Types of connections
When an FTP client connects to an FTP server it opens
a connection to the FTP control port 21.
Then the client tells the FTP server whether to
establish an active or passive connection.
The type of connection chosen by the client
determines how the server responds and on what ports
transactions will occur.

12. Active Connections
•When an active connection is established, the
server opens a data connection to the client from
port 20 to a high range port on the client machine. All
data from the server is then passed over this
connection.

13. Passive Connections
When a passive connection is established, the client
asks the FTP server to establish a passive connection
port, which can be on any port higher than 10,000.
The server then binds to this high-numbered port for
this particular session and relays that port number
back to the client. The client then opens the newly
bound port for the data connection.
Each data request the client makes results in a
separate data connection. Most modern FTP clients
attempt to establish a passive connection when
requesting data from servers.

15. Problems with FTP
1-FTP does not interpret the contents of a file
transferred in binary mode -- this can cause problems,
e.g. a file of 32-bit floating point numbers where the
representation is different on the two computers.
2-it doesn't use strong authentication.
3-It is based on password logins which can be
guessed, or discovered by cybercriminals using a
sniffer.
4-FTP sends files in clear plain-text
5-The main reason that web sites get hacked is
because they are being updated with insecure FTP
transfers.