1. Chapter 4 Communicating on the Internet

2. How E-Mail Works? Most used Feature TCP breaks & reassembles messages into packets IP delivers packets to the proper location Binary files can be attached: - Pictures - Video - sounds

3. How E-Mail Works?

4. Encoding schemes: MIME - UUencode Gateways perform translating email formats Mailing List: connects a group of people Everyone in the mailing list receive the sent message Moderated mailing list: screened by Admin Unmoderated mailing list: wide open List server

5. How Spam Works? Spam: - Unsolicited junk e-mail sent by commercial companies for some services - Unwanted mail, making another information slower to send - E-mail filters block Spam from known spammers

6. Spam Mails

7. How Usenet Newsgroups Work? The world biggest discussion forum Special software, online services Thread: grouped conversation by topics FAQ: Many newsgroups have a list of Frequently Asked Questions to read before submitting messages Moderated newsgroups: screened by Admin Unmoderated newsgroups: Automatically posted

8. Usenet Newsgroups Usenet Server: you can subscribe to any interested newsgroups or cancel it You can post Binary files UUencode: common used encoding scheme for Usenet newsgroups

9. Usenet Newsgroups

10. Internet Relay Chat Communicating with others (keyboard conversation) IRC: Internet Relay Chat, the most popular chatting way Channels: many different topics in chat rooms IRC follows a client/ server model: IRC Server IRC Client

11. Making Phone Calls on the Internet Sounds are broken into packets, which delivered by TCP/IP protocols Free calls Making phone calls and receiving calls from someone who has an Internet address WebTalk Speaking into microphones, listening from speakers