Ch11 NAT - Theory

Question 1

NAT Definition

Answer 1

1. Network Address Translation

2. Method of allowing an internal network address to be routed globally.

Question 2

Class A Private Addresses & CIDR Prefix

Answer 2

1. 10.0.0.0 - 10.255.255.255

2. 10.0.0.0 /8

Question 3

Class B Private Addresses & CIDR Prefix

Answer 3

1. 172.16.0.0 - 172.31.255.255

2. 172.16.0.0 /12

Question 4

Class C Private Addresses & CIDR Prefix

Answer 4

1. 192.168.0.0 - 192.168.255.255

2. 192.168.0.0 /16

Question 5

4 Types of NAT Addresses

Answer 5

1. Inside Local Address
2. Inside Global Address
3. Outside Local Address
4. Outside Global Address

Question 6

Inside Local Address

Answer 6

Address of the source as seen from inside the network

Question 7

Inside Global Address

Answer 7

Address of the source as seen from outside the network.

Question 8

Outside Local Address

Answer 8

Address of the destination as seen from inside the network.

Question 9

Outside Global Address

Answer 9

Address of the destination as see from outside the network.

Question 10

How is NAT terminology applied?

Answer 10

Applied from the perspective of the device with the translated address.

Question 11

Inside Address

Answer 11

Address of the device which is being translated by NAT

Question 12

Outside Address

Answer 12

Address of the destination device.

Question 13

Local Address

Answer 13

Any address that appears on the inside portion of the network.

Question 14

Global Address

Answer 14

Any address that appears on the outside portion of the network.

Question 15

3 Types of NAT Translation

Answer 15

1. Static Address Translation (Static NAT)
2. Dynamic Address Translation (Dynamic NAT)
3. Port Address Translation (PAT)

Question 16

Static NAT Definiton

Answer 16

One to one address mapping between local and global addresses.

Question 17

Dynamic NAT Definition

Answer 17

Many to many address mapping between local and global addresses.

Question 18

How are Dynamic NAT Addresses Assigned

Answer 18

From a public address pool on a 1st come 1st served basis.

Question 19

PAT Definition

Answer 19

Many to one mapping between local and global addresses.

Question 20

Another Name for PAT

Answer 20

NAT Overloading / Overloading

Question 21

Advantages of NAT (4)

Answer 21

1. Conserves the legally registered addressing scheme.
2. Increases the flexibility of connections to the public network
3. Provides consistency for internal network addressing schemes.
4. Provides some network security.

Question 22

Disadvantages of NAT (5)

Answer 22

1. Performance is degraded
2. End to end functionality is degraded
3. End to end IP traceability is lost
4. Tunneling becomes more complicated
5. Initiating TCP connections can be disrupted.

Question 23

Port Forwarding

Answer 23

Forwarding a network port from one network node to another; static NAT translation with a specified TCP or UDP number.

Question 24

Unique Local Addresses

Answer 24

IPv6 addresses designed to provide IPv6 address space for communications within a local site.

Question 25

What is the prefix for ULA Address

Answer 25

FC00 ::/7

Question 26

Breakdown of ULA Address

Answer 26

1. Prefix FC00::/7 (7 bits)
2. Locally Assigned (1 bit)
3. Global ID (40 bits)
4. Subnet ID (18 bits)
5. Interface ID (64 bits)