Section 7

Question 1

IPv4 addresses

Answer 1

are written as 4 octets, such as 192.168.4.12

Question 2

Dotted Decimal notation

Answer 2

a shorthand to represent 32 0’s and 1’s (256 combos)
Each octet is valued between 0 and 255
To convert from binary to dotted decimal add the values of the 1’s. Far left is 128 and half for each # going right. 128, 64, 32, 16, 8, 4, 2, 1.

Question 3

ARP (Address Resolution Protocol)

Answer 3

resolves MAC addresses from IP addresses. Type arp -a to see the ARP cache

Question 4

Class Licenses: Class A 0-126 /8, Class B 128-191 /16, Class C 192-223 /24

Answer 4

Classful subnetting was the first effort to divide networks IDs
Subnetting divides Network IDs into two or more networks
Regular IP addresses cannot end in 0 or 255 but subnets can
Subnets don’t have to be on the dots

Question 5

Computers on a network all have the same Network ID but different Host IDs

Answer 5

Cannot use 0-255 for the Host ID
The Subnet mask is only used by the computer- it is never sent out
The default gateway will figure out where to forward the message
Host uses the subnet mask to know if the destination is on the local network or a remote network

Question 6

Classless Inter-Domain Routing (CIDR)

Answer 6

can go past a /24 where that extra # can be a 1 or 0. In the Network ID if it is a 0 the Host ID can be from 1-126. If it is a 1 then the host id can be from 129 to 254.
2 subnets, 126 host per subnet
4 subnets, 62 host per subnet

Question 7

DHCP- Dynamic Host Configuration Protocol

Answer 7

Each broadcast domain must have only one DHCP server
DHCP server has to be run with broadcast domain
DHCP Relay enables a single DHCP server to service more than one broadcast domain

Question 8

APIPA - Automatic Private IP Addressing

Answer 8

APIPA addresses always start with 169.254

Question 9

Rogue DHCP servers

Answer 9

Two DHCP servers going simultaneously
If you get an IP address other than your correct network ID

Question 10

10.x.x.x

Answer 10

private IP addresses

Question 11

172.16.x.x - 172.31.x.x

Answer 11

private IP addresses

Question 12

192.168.x.x

Answer 12

private IP addresses

Question 13

NAT device

Answer 13

hides you from the Internet

Question 14

Loopback address

Answer 14

Loopback adapter you plug in and connect to yourself (IPv4 loopback - 127.0.0.1)
IPv6 loopback- ::1
APIPA- 169.254.x.x

Question 15

IP addressing scenarios:

Answer 15

Duplicate IP addresses- Know your network, run commands
Duplicate MAC addresses-
Incorrect gateway- Man in the middle attack
Incorrect subnet mask- all computers within the same broadcast domain will always have the same subnet mask
Expired IP address-