Tag: FTP Port

File Transfer Protocol | FTP Protocol

Computer Networks

Application Layer Protocols-

 

Important application layer protocols are-

 

 

  1. Domain Name Service (DNS)
  2. Hyper Text Transfer Protocol (HTTP)
  3. Simple Mail Transfer Protocol (SMTP)
  4. Post Office Protocol (POP)
  5. File Transfer Protocol (FTP)

 

In this article, we will discuss about File Transfer Protocol (FTP).

 

File Transfer Protocol-

 

  • FTP is short for File Transfer Protocol.
  • It is an application layer protocol.

 

Purpose-

 

  • It is used for exchanging files over the internet.
  • It enables the users to upload and download the files from the internet.

 

Working-

 

FTP establishes two TCP connections between the client and the server.

  • One connection is used for transferring data.
  • Other connection is used for transferring control information.

 

 

Characteristics of FTP-

 

  • FTP uses TCP at the transport layer.
  • FTP uses port number 21 for control connection.
  • FTP uses port number 20 for data connection.
  • FTP uses persistent TCP connections for control connection.
  • FTP uses non-persistent connections for data connection.
  • FTP is a connection oriented protocol.
  • FTP is an out-of-band protocol as data and control information flow over different connections.
  • SMTP is a stateful protocol.

 

Important Notes-

 

Note-01:

 

Emails can’t be sent using FTP.

 

This is because-

  • FTP requires the connection establishment between the client and server before transferring the files.
  • So, both have to be online at the same time.
  • That is why, emails are not sent using FTP.

 

Note-02:

 

FTP can transfer one file at a time.

 

  • FTP is used for transferring one file at a time in either direction between the client and the server.

 

Note-03:

 

FTP is a stateful protocol.

 

This is because-

  • The client establishes control connection for the duration of an FTP session.
  • It typically spans multiple data transfers.
  • So, FTP is a stateful protocol.

 

To gain better understanding about File Transfer Protocol,

Watch this Video Lecture

 

Next Article- Comparison of Application Layer Protocols

 

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