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Advanced IP Features

The preceding chapter introduced you to ACLs, one of the advanced features of the router’s IOS. This chapter covers two more advanced features: address translation and the Dynamic Host Configuration Protocol (DHCP). Address translation allows you to change the source or destination address inside the IP packet. This is typically done if you are using private IP addresses inside your network, or have overlapping addresses. The first half of this chapter provides an overview of address translation, including the many terms used and the different types of address translation and its configuration. The second half of this book has a brief overview of DHCP, which allows you. | CCNA CISCO CERTIFIED NETWORK ASSOCIATE 14 Advanced IP Features Two-Minute Drill Q A Self Test 14.02 Address Translation Configuration 2 Chapter 14 Advanced IP Features FTI k . . .k Jk . _ he preceding chapter introduced you to ACLs one of the advanced features of the router s IOS. This chapter covers two more advanced features address translation and the Dynamic Host Configuration Protocol DHCP . Address translation allows you to change the source or destination address inside the IP packet. This is typically done if you are using private IP addresses inside your network or have overlapping addresses. The first half of this chapter provides an overview of address translation including the many terms used and the different types of address translation and its configuration. The second half of this book has a brief overview of DHCP which allows you to assign and acquire IP addressing information dynamically and its configuration. CERTIFICATION OBJECTIVE 14.01 Address Translation Overview Address translation was originally developed to solve two problems handling a shortage of IP addresses and hiding network addressing schemes. Most people think that address translation is used primarily to solve the first problem. However as the first half of this chapter illustrates address translation provides solutions for many problems and has many advantages. Running Out of Addresses Because of the huge Internet explosion during the early 1990s it was foreseen that the current IP addressing scheme would not accommodate the number of devices that would need public addresses. A long-term solution was conceived to address this it called for the enhancement of the TCP IP protocol stack including the addressing format. This new addressing format was called IPv6. Whereas the current IP addressing scheme IPv4 uses 32 bits to represent addresses IPv6 uses 128 bits for addressing creating billions of extra addresses. Private Addresses It took a while for IPv6 to become a standard and on