Networking / Beginners

TCP

The Transmission Control Protocol (TCP) is how TCP/IP does connection-oriented communication. TCP is by far the most common type of session on a typical TCP/IP network. For example two computers, one Server and second one Client. One computer (Server) runs a Web server and the other (Client) runs a Web browser. When you enter a computer's address in the browser running on Client, it sends a single SYN (synchronize) packet to the Web server. If Server gets that packet, it sends back a single SYN, ACK (synchronize, acknowledge) packet. Client then sends Server a single ACK packet, and immediately requests that Server begin sending the Web page.

Once Server completes sending the Web page, it sends a FIN (finished) packet. Client responds with an RST, ACK (reset, acknowledge) packet and the session is over.

Most TCP/IP applications use TCP because connection-oriented sessions are designed to check for errors. If a receiving computer detects a missing packet, it just asks for a repeat as needed.

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In this tutorial:

  1. TCP/IP Applications
  2. Transport Layer Protocols
  3. TCP
  4. UDP
  5. ICMP
  6. IGMP
  7. The Power of Port Numbers
  8. Registered Ports
  9. Connection Status
  10. Rules for Determining Good vs. Bad Communications
  11. Common TCP/IP Applications
  12. HTTP
  13. Publishing Web Pages
  14. Web Servers and Web Clients
  15. Secure Sockets Layer and HTTPS
  16. Telnet
  17. Telnet Servers and Clients
  18. Configuring a Telnet Client
  19. Rlogin, RSH, and RCP
  20. SSH and the Death of Telnet
  21. E-mail
  22. SMTP, POP3, and IMAP4
  23. Alternatives to SMTP, POP3, and IMAP4
  24. E-mail Servers
  25. FTP
  26. Passive vs. Active FTP