SMTP,POP3,FTP & VoIP

SMTP

(SIMPLE MAIL TRANSFER PROTOCOL)

SMTP stands for Simple Mail Transfer Protocol. SMTP is used when email is delivered from an email client, such as Outlook Express, to an email server or when email is delivered from one email server to another. SMTP uses port 25.

POP3

(POST OFFICE PROTOCOL)

POP3 stands for Post Office Protocol. POP3 allows an email client to download an email from an email server. The POP3 protocol is simple and does not offer many features except for download. Its design assumes that the email client downloads all available email from the server, deletes them from the server and then disconnects. POP3 normally uses port 110.

COMPARISON  BETWEEN SMTP &POP

  POP is a protocol for storage of email. SMTP is a protocol for sending and receiving.

     

              To give a real-world illustration, SMTP would be like a letter carrier or mailman. He or she can deliver or pick up mail for transfer to another location. POP is like a mailbox or Post Office Box. It is the location the mail is delivered to and where it stays until the recipient is ready to read it. Outgoing mail can also be put in the mailbox.

           SMTP is the standard by which the vast majority of mail of transferred on the Internet. Though invented in the early 1980s, it has a reputation for being very reliable. Most mail goes through without problems and gets to the recipient quickly.

           However, SMTP also has some shortcomings that were not anticipated when it was first created, and that has created issues for many modern users. SMTP has no way of verifying senders are who they claim they are. Back in the 1980s, when the Internet was used among a select group of people mainly in government and academia, this was not a big issue.

      Since the 1990s, it has become a major problem. SMTP’s shortcomings, have given rise not only to spam, but a host of other more malicious enterprises, such as virus transfers. If a program can search an inbox and send a virus as an attachment to everyone on a certain person’s contact list, using that person’s name, it is more likely to be opened by the recipient, who trusts the person they think it is coming from. Though efforts have been made to increase the security of the SMTP standard, it is still a long way from being truly effective.

     POP was first designed in 1984 with the idea of allowing users to access an e-mail server, retrieve messages to a local folder located on the computer, and then go offline for reading and writing replies. In part, the offline capabilities were developed at a time when logging on to the Internet was relatively expensive and users were charged per minute. Currently, most of those using the POP standard are using the third version, developed in 1988. This is often referred to as POP3.

FTP

(FILE TRANSFER PROTOCOL) 

FTP means File Transfer Protocol, it is used to send larger packets of data than the traditional TCP/IP protocol. This is usually used when you download programs or documents from the internet.FTP normally uses port 21.

   As an example if u are owning a website,which obviously contains files and data s according to the requirement.. we have to transfer our files to display on the webpage or to execute on the website.FTP is used for transfering our file to the website or to download updated files from the website. basically FTP is the way of communication to the web server.

VOIP

 VOICE OVER IP (VOICE OVER INTERNET PROTOCOL, VOIP)

Voip is a methodology and group of technologies for the delivery of voice communication and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. Other terms commonly associated with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, IP communications, and broadband phone service.

        VoIP is a technology that allows telephone calls to be made over computer networks like the Internet. VoIP converts analog voice signals into digital data packets and supports real-time, two-way transmission of conversations using Internet Protocol (IP).

       VoIP calls can be made on the Internet using a VoIP service provider and standard computer audio systems. Alternatively, some service providers support VoIP through ordinary telephones that use special adapters to connect to a home computer network. Many VoIP implementations are based on the H.323 technology standard.
     
     VoIP offers a substantial cost savings over traditional long distance telephone calls. The main disadvantage of VoIP is a greater potential for dropped calls and degraded voice quality when the underlying network links are under heavy load.