slides14

Question 1

Host part all 0s

Answer 1

Originally specified to refer back to the originating host

Question 2

Host part all 1s

Answer 2

broadcast address to network.

Question 3

127.0.0.0: the loopback network, describe

Answer 3

The address 127.0.0.1 is commonly used as a way for a host to send a packet to itself over the internal loopback network on interface lo.

Question 4

what is a subnet

Answer 4

just another network, administered by smaller peopler

we further split the host part into some bits for the subnetwork and the rest for the actual hosts

Question 5

Three Bears Problem

Answer 5

There are no class Bs left: they have all been allocated

Question 6

what are solutions to Three Bears Problem

Answer 6

• Change the way classes are defined and used
• Use private addresses with network address translation
• Increase the number of addresses available by changing the IP

Question 7

Classless Interdomain Routing (CIDR)

Answer 7

(also called supernetting) Starting with about 32 million addresses per region
This allows easy routing: anything 194 or 195 goes to Europe
Repeat the idea within each region: contiguous block of C networks are allocated to ISPs or organisations

Question 8

is CIDR good

Answer 8

CIDR has allowed the continued growth of the Internet well beyond the original possible size

Question 9

Network Address Translation (NAT)

Answer 9

Network Address Translation (NAT) uses the malleability of packets to map many hosts onto a single address

Question 10

how can it be possible to do a one-to-many match

Answer 10

A gateway host joins the private network to the public Internet, modifying the addresses on packets as they go past

Question 11

NAT implicit security?

Answer 11

nat hides your private address from potential attackers