Shooting trouble with IP is not just crossing the bridge to get to the beach. As more and more companies are adopting IP-based networks, network engineers and analysts must continue to ensure the internetworks are available, reliable, redundant, responsive, accessible, and secure. Every one of you must understand TCP/IP end-to-end issues and know where to find the right tools and use the proper methods to make the IP world happy. This chapter reviewed IP protocols and packets, addressing, and routing protocol topics to get you started with IP troubleshooting. The next chapter examines IPX and many other hidden troubleshooting issues. Then the focus turns to Layer 2 LAN and WAN technologies to continue to build your practical troubleshooting skills.