This course discusses main protocols of Internet from everyday user's perspective, including IP, ARP, TCP, UDP, DNS, FTP, HTTP, HTTPS, SMTP, POP and P2P, etc. The course introduces details about the protocols related to everyday use, also concerns about the deployment of typical client software in application layer. It discusses several examples about how to find chemical information from Internet at the end. Students who take the course don't need much theory about computer science, but better have some experiences of computer, especially the experiences of surfing Internet with computer. Students can better understand main protocols of Internet through the course, may help solving the problems when using Internet.