Communicating on the Internet

Email Clients and Servers
Emails use client/server technology. Whether you use software made solely for email (such as Outlook) or a web-based service (such as Gmail) the client is what lets you perform the tasks like reading or sending emails and downloading attachments. The email client also communicates with email servers. When using programs like Outlook, you must give them information that allows it to connect to the email server that you use. Once it has the information, it streamlines the process, making it easier and simpler for you.

How Email is Delivered over the Internet
Once the message is sent, the email client connects to a Simple Mail Transfer Protocol (SMTP) server for the email domain (the part of the email after @). The email client tells the server who the emails from and sent to who. The SMTP asks the DNS server to ask for the IP address of the domain in question. The SMTP connects to the domain and gives the message to its SMTP server. POP3 and IMAP are two types of incoming-mail servers. When receiving a message from POP3, you download it from the server onto the computer. When getting a message from IMAP servers, the email stays on the server until you delete it. You can access the message from any computer.

How Instant Messaging Works
(IM) Instant Messaging has been around since the early 1990s. Its an alternative chat room online. Today, you can send and receive files, create chat rooms, and send messages from your phone as well. The client sends the server your IP address and any information about your contacts.