Experienced hackers understand how to exploit network operations through the Transmission Control Protocol/Internet Protocol (TCP/IP) stack.
They are also knowledgeable as to how a packet is constructed and routed. The goal of network and security administrators is to protect against hacker intrusions. This requires extensive knowledge of the TCP/IP suite to properly program firewall filters. In this module, you will learn the critical aspects of each of the TCP/IP layers.

When you have completed this module, you should be able to

1. Describe how network security is affected at the Transmission Control Protocol/Internet Protocol (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 theOpen Systems Interconnect (OSI) model and how packets are sent across the Internet

Open Systems Interconnect (OSI): A model for for network communications standardized by ISO, containing seven primary layers; the physical, data link, network, transport, session, presentation and applications.