1. .::Network Address Translation::. (NAT) By Tim Kaddoura (CS158B // Dr. Stamp)

2. IP Address Allocation Overview IPv4 – address length is 4 bytes long. IPv6 – address length is 16 bytes long. 2 32 V.S 2 128

3. Got NAT?! NAT operates at the network layer of the OSI reference model NAT is a hotel receptionist NAT allows for a “one to one”, “one to many”, or “many to many” mapping

4. NAT in Different Flavors Static NAT: (one to one) from unregistered (local) to registered (global). Dynamic NAT: (one to one) similar to Static Nat, but assigns from a pool of registered IP addresses. Overloading: (many to one) Most common NAT at homes and small businesses. Overlapping: (many to many) Most common in organizations.

5. NAT Operation GENERAL View Overloading View

6. NAT Operation (using a table) Source Computer Source Computer's IP Address Source Computer's Port NAT Router's IP Address NAT Router's Assigned Port Number A192.168.32.10400215.37.32.2031 B192.168.32.1350215.37.32.2032 C192.168.32.153750215.37.32.2033 D192.168.32.18206215.37.32.2034

7. NAT and Built-In Security NAT acts as a firewall. Trudy will have trouble if she is outside the network. How about Trudy being inside the network?!

8. NAT and SNMP Problem, problem, and some more problems! SNMP’s crucial IP information is no longer known. Solution: IBM’s Comprehensive Network Address Translator (CNAT).

9. To NAT or not to NAT!? NAT is a good interim solution. NAT is scalable. NAT offers some security. … To NAT!