IP Addressing

Question 1

Internet Protocol (IP) Address

Answer 1

o An assigned numerical label that is used to identify Internet communicating
devices on a computer network
▪ Layer 2
● Between two devices that are internal to own network or LAN
▪ Layer 3
● Between two different networks or even two different subnets

Question 2

Internet Protocol Version 4 (IPv4) Addressing

Answer 2

Written in dotted-decimal notation
● 10.1.2.3
● 172.21.243.67
▪ Each IPv4 address is divided into 4 separate numbers and divided by dots
▪ Each of these divisions are called octets due to having 8 bits assigned
▪ 32-bits in length

▪ IPv4 address is divided into network and host portions
▪ Subnet mask defines the network portion
● Network portion if a binary 1
● Host portion if binary 0

Question 3

Classes of IP Addresses

Answer 3

▪ Default subnet mask assigned by first octet
● Classful Masks if using default subnet mask

Class A—–1-126——255.0.0.0——/8
Class B——128-191—-255.255.0.0—-/16
Class C——192-223——255.255.255.0—–/24
Class D—-224-239——-n/a—-n/a

Question 4

Routable IPs

Answer 4

▪ Publicly routable IP addresses are globally managed by ICANN
● Internet Corporation for Assigned Names and Numbers
o ARIN, LACNIC, AFNIC, APNIC, and RIPE NCC
▪ Public IP’s must

Question 5

Private IPs

Answer 5

▪ Private IP’s can be used by anyone
▪ Not routable outside your local area network
▪ Network Address Translation (NAT) allows for routing of private IPs
through a public IP

Question 6

Specialized IPs

Answer 6

Loopback addresses (127.x.x.x range)
● Refers to the device itself and used for testing
● Most commonly used as 127.0.0.1
Automatic Private IP Addresses (APIPA)
● Dynamically assigned by OS when DHCP server is unavailable and
address not assigned manually
● Range of 169.254.x.x

Question 7

Virtual IP Addresses (VIP or VIPA)

Answer 7

▪ An IP address that does not correlate to an actual physical network
interface
▪ respond to numerous IP addresses and have them resolve to your
physical network interface to establish connectivity

Question 8

IPv4 Data Flows:
Unicast

Answer 8

▪ Data travels from a single source device to a single destination device

Question 9

Ipv4 Data Flows
Multicast:

Answer 9

Data travels from a single source device to multiple (but specific)
destination devices

Question 10

Ipv4 Data Flows
Broadcast:

Answer 10

Data travels from a single source device to all devices on a destination
network

Question 11

Assigning IP Addresses
Static:

Answer 11

▪ Simple
▪ Time-consuming
▪ Prone to human errors
▪ Impractical for large networks

Question 12

Assigning IP Addresses
Dynamic:

Answer 12

▪ Quicker
▪ Easier
▪ Less confusing
▪ Simplistic for large network

Question 13

Components of an IP Address

Answer 13

Information assigned from static or dynamic
● IP Address
● Subnet Mask
● Default Gateway
● Server addresses
o Domain Name System (DNS)
▪ Converts domain names to IP address
o Windows Internet Name Service (WINS)
▪ Converts NetBIOS computer name into an IP
address

Question 14

Dynamic Host Control Protocol (DHCP) Configuration

Answer 14

▪ Based on the older Bootstrap Protocol
(BOOTP for short)
● Required static database of IP and
MAC to assign
▪ DHCP service assigns an IP from an
assignable pool (scope)
▪ IP Address Management is software
used to manage the IP’s being assigned

Question 15

Dynamic Host Control Protocol (DHCP)

Answer 15

▪ Provides clients with
● IP
● Subnet mask
● Default gateway
● DNS server
● WINS server
● Other variables needed for VoIP
▪ Each IP is leased for a given amount of time and given back to the pool
when lease expires (TTL)

Question 16

Automatic Private IP Address (APIPA)

Answer 16

Used when device does not have a
static IP address and cannot reach a
DHCP server
▪ Allows a network device to self-assign
an IP address from the 169.254.0.0/16
network
▪ Designed to allow quick configuration of
a LAN without need for DHCP
▪ Non-routable but allows for network
connectivity inside the local subnet

Question 17

Zero Configuration (Zeroconf)

Answer 17

Newer technology based on APIPA providing:
● Assigning link-local IP addresses
o Non-routable IP usable only on local subnet
● Resolving computer names to IP addresses without the need for
DNS server on local network
o mDNS - Multicast Domain Name Server
● Locating network services
o Provides service discovery protocols
▪ Service Location Protocol (SLP)
▪ Microsoft’s Simple Service Discovery Protocol
(SSDP)
▪ Apple’s DNS-based Service Discovery (DNS-SD)