What are SMTP, FTP and POP3

Posted by Bhavesh Joshi On Friday, November 23, 2012 0 comments

SMTP Server
SMTP (Simple Mail Transfer Protocol) servers run the SMTP protocol. After you connect with a SMTP Server (which your e -mail consumer will after you send a message), your laptop can send it all the data within the message, as well as admitting who it is from, wherever it's going, and what trying to says. The SMTP server then dispatches it to a mail server, wherever the recipients' names are hunted on a DNS (domain name server), and so the message are delivered. The recipient can receive the message, unremarkably through POP3 (Post Office Protocol). So finally, SMTP server is that the opening step to delivering an email message. 

Working of SMTP 

SMTP defines the format for messages sent between TCP/IP hosts on the net. SMTP generally use plain 7-bit ASCII text to dispatch e-mail messages and to issue SMTP commands to receiving hosts. Multipurpose Internet Mail Extensions (MIME) is often used to encode multipart binary files as well as attachments into a kind that SMTP will handle. 

SMTP provides a mechanism for forwarding e-mail from one TCP/IP host to a different over the net. SMTP services using on a TCP/IP host prior develop a connection to a remote host through Transmission Control Protocol (TCP) port Twenty Five (25). SMTP session is then initiated by a dispatching a hello command and after it, receiving an OK response. The dispatching system (computer) is then, uses the subsequent commands to send messages: 

Mail fr : Identifies the dispatching (sending) host to the receiving host. 

Rcpt to : Identifies the targeted message recipient to the receiving host through the Domain Name System (DNS) format user@DNSdomain. 

Data : Initiates the dispatching (sending) of the message body as a series of lines of ASCII text and it ends with a single period (.) with on a line. 

Quit : Closes the SMTP affiliation (connection). 

Note : SMTP provides message transport solely from one SMTP host to a different. Support for storing messages in mailboxes is provided by Post Office Protocol V3 (Version 3) (POPS) and Internet Mail Access Protocol V4 (IM4P4). 

What is File Transfer Protocol (FTP)

File Transfer Protocol  File Transfer Protocol (FTP) is a standard kind of Internet protocol, is that the easiest method to exchange files between computers on the net. Just like the Hyper- text Transfer Protocol (HTTP), who transfers displayable websites and similar files, and the Simple Mail Transfer Protocol (SMTP), that transfers electronic mail, FTP is an application protocol which uses the Internet's TCP/IP protocols. FTP is often used to deliver website files from their creator to the pc (computer) that acts as their server for everybody on the net. It is also unremarkably used to transfer or download programs and other files to your laptop from alternative servers. FTP is that the most well-liked methodology of exchanging files as a result of it's quicker than alternative protocols like hypertext transfer protocol (HTTP) or POP (Post Office Protocol). If you would like to exchange giant files, you must take into account FTP. FTP content is dispatched and received by pc (computer) port 21 and below the transmission control protocol. 

The transfer is asynchronous, that means not at constant time, and thus quicker than alternative protocols. 

Objectives of FTP were:
I. FTP is used to promote sharing of files as computer programs and/or data.
II. It is used to encourage indirect or implicit (via programs) use of remote computers.
III. To defend a user from variations in file storage systems among hosts and
IV. It is used to transfer content faithfully and with efficiency. 

FTP is meant chiefly to be used by programs although it's usable directly by a user at a terminal. 

Useful FTP Commands are as follows -

1. ascii : This command is used to make changes to text mode. It is necessary for uploading a homepage file (index.html). ASCII stands for American Standard Code for Information Interchange.

2. Binary : Changes to binary mode. Necessary to transfer (upload) a computer file, like an image. 

3. Dir : List files, with additional information than "Lbs".

4. put (filename) : transfer or upload (filename) from your machine. 

5. get (filename) : transfer or upload (filename) to your machine. 

6. CD (directory name) : Changes directory on the remote machine. 

7. LCD (directory name) : It is used to changes directory on your native (home) pc. 

8. mg et (files) : This command is used to download multiple files to your machine. 

9. mp ut (files) : This command is used to download multiple files from your machine. 

10. bye : shut the ftp session. 

11. quit/close/bye/disconnect : to disconnect from the FTP server. 

12. facilitate : Shows an inventory of obtainable ftp commands.

What's POP3 (Post Office Protocol Version 3)

POP3
An Internet standard protocol for stocking and retrieving data (messages) from SMTP hosts. SMTP provides the Underlying transport mechanism for dispatching electronic mail messages over the net, however it doesn't offer any facility for storing messages and retrieving them. SMTP hosts should be always connected from one to other, however most users don't have a passionate connection to the net. 

POP3 provides mechanisms for stocking messages sent to every user and received by SMTP in a very receptable known as a mailbox. A POP3 server stores messages for every user till the user connects to transfer or download and watch them through a POPS consumer like Microsoft Outlook, Microsoft Mail and News or Microsoft Outlook Express. To retrieve a message from a POPS server, a POPS consumer develpos a transmission control protocol session through transmission control protocol port 110, identifies itself to the server, and after it issue a series of POP3 Commands as stat, list, retr, quit etc.

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