IP Addressing
CompTIA Network+ N10-009
IP Addressing
Covering IPv4 classes, private/APIPA ranges, unicast/multicast/broadcast, IPv6 structure, EUI-64, and dual-stack/tunneling migration strategies.
01 · IPv4 Addressing
Hierarchical IPv4 Structure
An IPv4 address is a 32-bit logical identifier divided into four octets. It is structured hierarchically into network and host portions to enable efficient routing.
// Exam Objectives Covered
- Domain 1.0: Networking Concepts
- 1.7 Use appropriate IPv4 network addressing
- Public vs. private (RFC1918)
- APIPA and Loopback
- IPv4 address classes (A, B, C, D, E)
- 1.8 Summarize modern network environments
- IPv6 addressing & compatibility
Class A (1-126)
First bit is always 0. First byte is the network address; remaining three bytes are for hosts. Default mask is 255.0.0.0 (/8).
Class B (128-191)
First two bits are 10. First two bytes are network; last two are hosts. Default mask is 255.255.0.0 (/16).
Class C (192-223)
First three bits are 110. First three bytes are network; last byte is hosts. Default mask is 255.255.255.0 (/24).
Class D (224-239)
Reserved for multicast addresses. Packets are sent from one source to multiple destinations.
Class E (240-255)
Reserved for scientific and experimental purposes. Cannot be assigned to hosts.
Address Types
Unicast (one-to-one), Broadcast (one-to-all on a subnet), and Multicast (one-to-many).
02 · Special & Private Addresses
Reserved IP Address Spaces
Certain IPv4 address ranges are reserved for specific functions, diagnostics, or private internal networks to prevent exhaustion of public IPs.
RFC 1918 (Private)
Not routable on the Internet; used internally and translated via NAT.
Class A: 10.0.0.0 - 10.255.255.255
Class B: 172.16.0.0 - 172.31.255.255
Class C: 192.168.0.0 - 192.168.255.255
Class A: 10.0.0.0 - 10.255.255.255
Class B: 172.16.0.0 - 172.31.255.255
Class C: 192.168.0.0 - 192.168.255.255
APIPA
Automatic Private IP Addressing. Used when a DHCP server is unavailable. Range is 169.254.0.1 through 169.254.255.254 with a 255.255.0.0 mask.
Loopback
127.0.0.1 is reserved for diagnostics. It allows a host to send a test packet to itself without generating network traffic.
Virtual IP (VIP)
An IP address that doesn't correspond to an actual physical interface. Commonly used on subinterfaces, load balancers, or proxy servers.
03 · IPv6 Addressing
The Next Generation Protocol
IPv6 solves the IPv4 exhaustion problem by using a 128-bit address space represented in hexadecimal. It eliminates broadcasts and mandates IPSec.
Global Unicast
Equivalent to a public IPv4 address. Routable on the Internet. Starts with 2000::/3.
Unique Local
Equivalent to a private IPv4 address. Globally unique but not routable on the Internet; routable internally. Starts with FC00::/7.
Link-Local
Equivalent to APIPA. Automatically configured, not routed at all. Starts with FE80::/10.
Anycast
One-to-nearest. Applied to multiple interfaces; packets are delivered to the closest one.
Multicast
One-to-many. Delivered to all interfaces identified by the address. Always starts with FF00::/8.
EUI-64
Autoconfiguration method. Pads a 48-bit MAC address with FFFE in the middle and inverts the 7th bit to create a 64-bit interface ID.
04 · Migration Strategies
Transitioning to IPv6
Because IPv4 and IPv6 are not directly compatible, transition mechanisms are required to allow networks to migrate gradually.
Dual Stacking
Devices run both IPv4 and IPv6 protocol stacks simultaneously. This is the most common and easiest migration strategy.
6to4 Tunneling
Encapsulates IPv6 packets inside IPv4 packets for transmission across an IPv4-only network. Uses protocol type 41.
Teredo
Encapsulates IPv6 traffic inside UDP packets to allow tunneling through NAT devices that normally break 6to4 tunnels.
10 · Written Lab
Practice Written Lab
Provide the appropriate term or value for each statement. Type your answer and press Enter or click outside the field to check.
1
What is the valid range of IP addresses used for Class C private networks?
Hint: Format X.X.X.0-X.X.X.255
2
What are some advantages of using IPv6 compared to IPv4?
Hint: Focus on the size
3
What autoconfiguration technology assigns IP addresses starting with 169.254?
4
How is a unicast address defined?
5
How is a multicast address defined?
6
What is the term for the 48-bit physical address assigned to a network interface card?
7
How many more bits does an IPv6 address have compared to an IPv4 address?
8
What is the private IP address range reserved for Class B networks?
Hint: Format X.X.X.0-X.X.X.255
9
What are the decimal values for the first octet of a Class C address range?
10
What is the purpose of the 127.0.0.1 IP address?
11
What type of IPv6 packet is addressed and delivered to a single interface?
12
Which type of IPv6 address functions similarly to a public, routable IPv4 address?
13
Which type of IPv6 address is strictly non-routable?
14
Which type of IPv6 address is globally unique but not routable on the Internet?
15
What type of IPv6 address is delivered to multiple interfaces simultaneously?
16
Which IPv6 address type identifies multiple interfaces but only delivers packets to the nearest one?
17
Which IPv6 addressing type is known as one-to-nearest?
18
What is the IPv6 equivalent of the IPv4 loopback address 127.0.0.1?
19
What prefix does a link-local IPv6 address always start with?
20
What prefix indicates a unique local unicast IPv6 address range?
11 · Review Quiz
Test Your Knowledge
20 review questions covering all the chapter material. Select the best answer for each question.
Question 1 of 20
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