Week 3: NAPT

Question 1

What is NAT?

Answer 1

A mechanism to translate (map) one address space by another

Question 2

What does NAT allow regarding IP Addresses?

Answer 2

NAT allows many private IP addresses to be represented by some smaller number of public IP addresses

Question 3

What was the original intention for NAT?

Answer 3

To slow down the depletion of available IP address space, similar to CIDR

Question 4

List some advantages of NAT

Answer 4

Conserves legally registered addresses
Remedies address overlap events
Increases flexibility when connecting to the internet
Eliminates address renumbering as a network evolves

Question 5

List some disadvantages of NAT

Answer 5

Translation results in switch path delays
Causes loss of end-to-end IP traceability
Certain applications will not function w/ NAT enabled

Question 6

List the types NAT

Answer 6

Static, Dynamic, and Overloading

Question 7

What is an Overloaded NAT known as?

Answer 7

Port Address Translation (PAT)

Question 8

What does Inside Local mean regarding NAT

Answer 8

Source host is inside address before translation (typically an RFC 1918 address)

Question 9

What does Outside Local mean regarding NAT?

Answer 9

Address from which source host is known to the Internet. This is usually the address of the router interface connected to ISP (actual internet address)

Question 10

What does Inside Global mean regarding NAT?

Answer 10

Source host address used after translation to get onto the Internet (this is also the actual internet address)

Question 11

What does Outside Global mean regarding NAT?

Answer 11

Address of outside destination host & the real internet address