1. Configuring NAT and PAT Chapter 18 powered by DJ 1

2. Chapter Objectives At the end of this Chapter you will be able to:  Implementing Network Addresses Translation (NAT)  Implementing Port Address Translation (PAT) powered by DJ 2

3. Network Address Translation (NAT) When Do We Use NAT? NAT is typically used on a border router. Here’s a list of situations when it’s best to have NAT on your side:  You need to connect to the Internet and your hosts don’t have globally unique IP addresses.  You change to a new ISP that requires you to renumber your network.  You need to merge two intranets with duplicate addresses. powered by DJ 3

4. Where to configure NAT powered by DJ 4

5. Advantages and Disadvantages of Implementing NAT powered by DJ 5

6. Types of Network Address Translation There are three types of NAT:  Static NAT This type of NAT is designed to allow one-to-one mapping between local and global addresses. Keep in mind that the static version requires you to have one real Internet IP address for every host on your network.  Dynamic NAT This version gives you the ability to map an unregistered IP address to a registered IP address from out of a pool of registered IP addresses. powered by DJ 6

7.  Overloading  This is the most popular type of NAT configuration. Understand that overloading really is a form of dynamic NAT that maps multiple unregistered IP addresses to a single registered IP address—many-to-one— by using different ports.it’s also known as Port Address Translation (PAT). And by using PAT (NAT Overload), you get to have thousands of users connect to the Internet using only one real global IP address. powered by DJ 7

8. How NAT Works:  To understand How Nat works, consider the figure: Basic NAT translation powered by DJ 8

9. NAT overloading example (PAT)  To understand Nat overloading, consider the following figure, NAT Overloading powered by DJ 9

10. Static NAT Configuration  ip nat inside source static 10.1.1.1 170.46.2.2  interface Ethernet0  ip address 10.1.1.10 255.255.255.0  ip nat inside  interface Serial0  ip address 170.46.2.1 255.255.255.0  ip nat outside powered by DJ 10

11. Dynamic NAT Configuration  ip nat pool hcl 170.168.2.2 170.168.2.254  netmask 255.255.255.0  ip nat inside source list 1 pool hcl  interface Ethernet0  ip address 10.1.1.10 255.255.255.0  ip nat inside  interface Serial0  ip address 170.168.2.1 255.255.255.0  ip nat outside  access-list 1 permit 10.1.1.0 0.0.0.255 powered by DJ 11

12. PAT (Overloading) Configuration  ip nat pool globalnet 170.168.2.1 170.168.2.1  netmask 255.255.255.0  ip nat inside source list 1 pool globalnet overload  interface Ethernet0/0  ip address 10.1.1.10 255.255.255.0  ip nat inside  interface Serial0/0  ip address 170.168.2.1 255.255.255.0  ip nat outside  access-list 1 permit 10.1.1.0 0.0.0.255 powered by DJ 12

13. Simple Verification of NAT  Router# show ip nat translation  Router#debug ip nat  To clear your NAT entries from the translation table, use the following command:  clear ip nat translation  To clear all entries from the NAT table, use an asterisk (*) at the end of the command. powered by DJ 13

14. Configuring NAT Using SDM There is more than one wizard. Again you get to pick between basic and advanced:  Basic NAT Use this wizard if you have some basic PCs/hosts on your trusted network that need access to the Internet. This wizard will guide you through the process of creating a basic NAT configuration.  Advanced NAT If you have servers on your inside network and the users from the outside need to access, you definitely want to opt for the Advanced NAT configuration. powered by DJ 14

15. The first screen is the Create NAT Configuration screen powered by DJ 15

16. Basic NAT Wizard is going to do. Now click Next to get to a screen from which I’m able to select all my inside and outside addresses. powered by DJ 16

17. Sharing the Internet Connection Finally, click Finish and it is done. powered by DJ 17

18. THANK YOU powered by DJ 18