Network Address Translation NAT By Tim Kaddoura CS
. : : Network Address Translation: : . (NAT) By Tim Kaddoura (CS 158 B // Dr. Stamp)
IP Address Allocation Overview n n n IPv 4 – address length is 4 bytes long. IPv 6 – address length is 16 bytes long. 232 V. S 2128
Got NAT? ! n n n 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
NAT in Different Flavors n n 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.
NAT Operation GENERAL View Overloading View
NAT Operation Source Co mp ute r Source Comp uter's IP Addre ss Source Com puter 's Port NAT Router's IP Addre ss NAT Router's Assign ed Port Numbe r A 192. 168. 32. 10 400 215. 37. 32. 203 1 B 192. 168. 32. 13 50 215. 37. 32. 203 2 C 192. 168. 32. 15 3750 215. 37. 32. 203 3 D 192. 168. 32. 18 206 215. 37. 32. 203 4 (using a table)
NAT and Built-In Security n n n NAT acts as a firewall. Trudy will have trouble if she is outside the network. How about Trudy being inside the network? !
NAT and SNMP n n n Problem, problem, and some more problems! SNMP’s crucial IP information is no longer known. Solution: IBM’s Comprehensive Network Address Translator (CNAT).
To NAT or not to NAT!? n NAT is a good interim solution. n NAT is scalable. n NAT offers some security. n … To NAT!
- Slides: 9