.::Network Address Translation::. (NAT)

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.
• 232 V.S 2128

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
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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
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
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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!
• SNMPs crucial IP information is no longer known.
• Solution IBMs Comprehensive Network Address
  Translator (CNAT).

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To NAT or not to NAT!?

• NAT is a good interim solution.
• NAT is scalable.
• NAT offers some security.
• To NAT!