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Lesson 9
TCP-IP-STACK Conclusion
This module discussed how hackers often exploit weaknesses in the TCP/IP stack of various Internet hosts to compromise a network's security.
Reviewing the basics of TCP/IP, you learned how packets are created and sent according to the OSI model, and saw how a network routes those packets.
If you understand how messages are sent across the Internet, you can take specific steps to ensure that your company is sending information as securely as possible.

Now that you have completed this module, you should be able to
  1. Describe how network security is affected at the TCP/IP levels
  2. Describe the physical and data link layers of a network
  3. Identify the Internet layer and its weaknesses
  4. Identify the Transport Layer (TCP/UDP)and its weaknesses
  5. Identify the application layer and its weaknesses
  6. Discuss the security implications of commonly used applications
  7. Describe the OSI model and how packets are sent across the Internet
Key terms and concepts
  1. Address Resolution Protocol (ARP):A network protocol that is used to convert IP addresses to physical network addresses by sending an ARP broadcast to request the address.
  2. Compressed Serial Line Internet Protocol (CSLIP): Compresses the IP and TCP headers, thus reducing the size of the packet and improving bandwidth.
  3. Daemon: A process that performs a specified operation at a predefined time or in response to certain events. Daemon is a UNIX term. In other operating systems such as Windows, daemons are referred to as services.
  4. Datagram: An IP packet.
  5. Denial-of-service: An attempt by attackers to prevent legitimate users of a service from using that service by flooding a network, or by disrupting connections or services.
  6. Encryption: The process of disguising a message to make it unreadable by humans. The resulting data is called ciphertext.
  7. File Transfer Protocol (FTP): An approved method that allows the delivery of files across the Internet. An FTP server stores directories of files using a hierarchical structure. Normally, a user is a client and a company acts as the server.
  8. Firewall: A security system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both.
  9. Hypertext Transfer Protocol (HTTP): A TCP/IP application that uses a browser to access and retrieve Web pages from the server.
  10. Transmission Control Protocol/Internet Protocol (TCP/IP): A suite of protocols that turns information into blocks of information called packets. These are then sent across networks such as the Internet.
  11. Internet Control Message Protocol (ICMP): A protocol used to communicate errors or other conditions at the IP layer
  12. Internet Assigned Numbers Authority (IANA): Oversees and coordinates the assignment of every unique protocol identifier used on the Internet.
  13. IP spoofing
  14. Network News Transfer Protocol (NNTP)
  15. Network topology
  16. Open Systems Interconnect (OSI)
  17. Packet
  18. Packet sniffer
  19. Point-to-Point Protocol (PPP)
  20. Proxy server
  21. Reverse Address Resolution Protocol (RARP)
  22. Screening router
  23. Serial Line Internet Protocol (SLIP)
  24. Simple Mail Transfer Protocol (SMTP)
  25. Simple Network Management Protocol (SNMP)
  26. Smurf attack
  27. TCP/IP protocol
  28. Telnet
  29. UDP (User Datagram Protocol)
  30. Virtual Private Network
  31. Winnuke
Protocol Layers Quiz
Click the quiz link below to take a multiple-choice quiz about the material we have covered in this module.
Protocol Layers Quiz
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