Email and Protocol

Email-

• it is a method of exchanging digital messages from sender to one or more recipients. Todays email system is based on a store and forward model.
  


• the sender and recipients do not have to be online at the same time. your email waits in the inbox from anywhere around the world.
  


• address book- within an email you can include peoples names, email address etc.
  


• attachments- you can send things such as photos and videos.
  


• you can send the same email to multiple recipients. you can people in to the email using the CC (carbon copy) field. recipients who are in this field will be visible to everyone the email is sent to. however if you dont want other people to see that the email has been sent to them
  

Email format- 3 parts

• sender and recipient address 
  


• subject line
  


• body
  

Protocol-

• simple mail transfer protocol (SMTP)
  


• internet message access protocol (IMAP)
  


• post office protocol3 (POP3)
  

 

 

 

SMTP- it is a connection-oriented text based protoco. it communicates with a mail sender and mail receiver by issuing comands. the 3 steps are mail command to establish the return address, RCPT command to establish a recipient of the message and data to send the message.

 IMAP-  is a protocol for email retrieval. its an application layer internet protocol that allows an e-mail client to access email on a remote mail server. email clients using IMAP generally leave messages on the server until the user explicitly deletes them. Incoming e-mail messages are sent to an e-mail server that stores messages in the recipients e-mail box.

 POP3- is an application layer internet standard protocol used by local e-mail clients to retrieve e-mail from a remote server over a TCP/IP connction. pop supports simple download and delete requirements for access to remote mail boxes.