IP Addressing

Question 1

What is an IP address?

Answer 1

A unique numerical label that identifies a device on a network, used for routing traffic.

Question 2

At which OSI layer does IP addressing function?

Answer 2

Layer 3 – the Network Layer.

Question 3

How do IP addresses differ from MAC addresses?

Answer 3

IP addresses are logical (Layer 3), change by location, and are used between networks; MAC addresses are physical (Layer 2), permanent, and used within LANs.

Question 4

What’s a good analogy for an IP address?

Answer 4

Like a mailing address – used to deliver data via routers, similar to postal hubs.

Question 5

What format does IPv4 use?

Answer 5

32-bit addresses written in dotted decimal (e.g., 192.168.1.1), divided into four 8-bit octets.

Question 6

How is the network and host portion of an IP address determined?

Answer 6

By the subnet mask (e.g., 255.255.255.0 means first three octets are network, last is host).

Question 7

What is 192.168.1.4 in binary?

Answer 7

11000000.10101000.00000001.00000100

Question 8

What are the IPv4 address class ranges and their use cases?

Answer 8

• Class A: 1–126 → Large orgs
• Class B: 128–191 → Medium orgs
• Class C: 192–223 → Small networks
• Class D: 224–239 → Multicast
• Class E: 240–255 → Experimental

Question 9

What are the default subnet masks for IPv4 classes A, B, and C?

Answer 9

• A: 255.0.0.0 (/8)
• B: 255.255.0.0 (/16)
• C: 255.255.255.0 (/24)

Question 10

What’s the difference between public and private IPs?

Answer 10

• Public IPs: Routable on the internet, assigned by ISPs
• Private IPs: Internal use only, defined by RFC 1918

Question 11

What are the private IP ranges?

Answer 11

• 10.0.0.0 – 10.255.255.255
• 172.16.0.0 – 172.31.255.255
• 192.168.0.0 – 192.168.255.255

Question 12

What are special IPv4 addresses and their use?

Answer 12

• Loopback (127.0.0.1): Internal system test
• APIPA (169.254.x.x): Auto-assigned when DHCP fails

Question 13

What are the types of IPv4 data flows?

Answer 13

• Unicast: One-to-one (e.g., web browsing)
• Multicast: One-to-many (e.g., streaming)
• Broadcast: One-to-all on local subnet (e.g., DHCP discover)

Question 14

What is the IPv4 broadcast address?

Answer 14

255.255.255.255

Question 15

What is the multicast IP range?

Answer 15

224.0.0.0 – 239.255.255.255

Question 16

What is static IP addressing used for?

Answer 16

Devices like servers or printers that require consistent IPs.

Question 17

What must be manually configured for a static IP?

Answer 17

IP, subnet mask, default gateway, and DNS.

Question 18

What is dynamic IP addressing?

Answer 18

Uses DHCP to automatically assign IPs from a predefined scope.

Question 19

What are other IP assignment methods?

Answer 19

• BOOTP: Predecessor to DHCP
• APIPA: Local-only auto-IP when DHCP fails
• ZeroConf: Self-configuration using mDNS (Bonjour, LLMNR)

Question 20

What is the purpose of subnetting?

Answer 20

To divide larger networks into smaller segments for efficiency and security.

Question 21

What formula calculates number of subnets?

Answer 21

2^s (s = bits borrowed from host portion)

Question 22

What formula calculates usable hosts per subnet?

Answer 22

2^h – 2 (h = host bits remaining)

Question 23

What is CIDR notation?

Answer 23

A shorthand for subnet masks (e.g., /24 = 255.255.255.0)

Question 24

Why was IPv6 developed?

Answer 24

To solve IPv4 address exhaustion.

Question 25

What is the format of an IPv6 address?

Answer 25

128-bit hexadecimal, separated by colons (e.g., 2001:0db8::1)

Question 26

What are the IPv6 shortening rules?

Answer 26

Remove leading 0s and use '::' once for consecutive zero blocks.

Question 27

What are the types of IPv6 addresses?

Answer 27

* Unicast (2000::/3): One-to-one * Link-local (FE80::/10): Auto-configured, local segment only * Unique Local (FC00::/7): Private networks * Multicast (FF00::/8): One-to-many * Anycast: One-to-nearest (IPv6 only)

Question 28

Does IPv6 use broadcast?

Answer 28

No – replaced by multicast and anycast.

Question 29

What are the types of IPv6 data flows?

Answer 29

* Unicast: One-to-one (e.g., 2001:db8::1) * Multicast: One-to-many (e.g., FF02::1) * Anycast: One-to-nearest (uses unicast address)

Question 30

What is Dual Stack?

Answer 30

Devices run both IPv4 and IPv6 simultaneously.

Question 31

What is tunneling in IPv6?

Answer 31

Encapsulates IPv6 packets inside IPv4 to traverse older networks.

Question 32

What is NAT64?

Answer 32

Translates IPv6 addresses to IPv4 to allow communication with IPv4-only systems.

Question 33

How do you convert binary to decimal?

Answer 33

Add the values of all positions with a 1.

Question 34

Convert binary 10010110 to decimal.

Answer 34

150 (128 + 16 + 4 + 2)

Question 35

How do you convert decimal to binary?

Answer 35

Subtract powers of 2 until you reach zero.

Question 36

Convert decimal 167 to binary.

Answer 36

10100111

Question 37

What is the usable host count for /24?

Answer 37

254 usable IPs (Subnet mask: 255.255.255.0)

Question 38

What is the usable host count for /30?

Answer 38

2 usable IPs (Subnet mask: 255.255.255.252)

Question 39

What is the purpose of a /31 subnet?

Answer 39

Point-to-point links (2 usable IPs)

Question 40

What is a /32 subnet used for?

Answer 40

Single host

Question 41

How many bits are in IPv4 and IPv6?

Answer 41

IPv4 = 32-bit, IPv6 = 128-bit

Question 42

What are the private IPv4 ranges?

Answer 42

* 10.x.x.x * 172.16.x.x – 172.31.x.x * 192.168.x.x

Question 43

What prefix do all IPv6 multicast addresses start with?

Answer 43

FF::

Question 44

What replaces broadcast in IPv6?

Answer 44

Multicast and Anycast

Question 45

What are the key subnetting formulas?

Answer 45

* Subnets = 2^borrowed bits * Usable Hosts = 2^host bits – 2

Question 46

What should you practice for IP addressing mastery?

Answer 46

CIDR notation, binary-to-decimal conversion, and subnet chart memorization.