All About IP Address And Classes IPv4 & IPv6

IP Address (Internet Protocol Address or often abbreviated as IP) is a series of binary numbers between 32-bit to 128-bit that are used as identification addresses for each host computer on an Internet network.

The length of this number is 32-bit (for IPv4 or IP version 4), and 128-bit (for IPv6 or IP version 6) which shows the address of the computer on TCP / IP-based Internet networks.

Internet Assigned Numbers Authority (IANA) which manages the allocation of global IP addresses. IANA works.

Internet Protocol (IP) address is a numeric address assigned to a computer that is participating in a computer network utilizing the Internet Protocol for communication between its nodes.

Although IP addresses are stored as binary numbers, they are usually displayed to make it easier for humans to use notations, such as (for IPv4), and 2001: db8: 0: 1234: 0: 567: 1: 1 (for IPv6).

The Internet Protocol also has the task of routing data packets between networks, IP addresses and determining the location of the source node and destination node in the topology of the routing system.

For this purpose, several bits in the IP address are used to designate a subnetwork. This number of bits is indicated in CIDR notation, which is added to the IP address, for example,


The IP addressing system is divided into two parts

  • IP version 4 (IPv4)
  •  IP version 6 (IPv6)

Sending data in TCP / IP networks based on the IP address of the sending computer and the receiving computer. The IP address has two parts, namely the network address (network address) and the address of the local computer (host address) in a network.

Network addresses are used by routers to search for networks where a local computer is located, while the address of a local computer is used to identify a computer on a local network. Read: 5 Best VPN Services

All About Ip Address And Classes IPv4 & IPv6

All About Ip Address And Classes IPv4 & IPv6


1. Address IP version 4

The IP address version 4 (often called IPv4 Address) is a type of network addressing used in the TCP / IP network protocol that uses the IP version 4. The total length is 32-bit, and theoretically can address up to 4 billion host computers or more precisely 4,294,967,296 hosts throughout the world, the number of hosts is obtained from 256 (obtained from 8 bits) on the 4th (because there are 4 octets) so that the maximum value of Alamt IP version 4 is where the value is calculated from zero so the Host value that can be accommodated is 256x256x256x256 = 4,294,967,296 hosts. so that if hosts that exist throughout the world exceed the quota, IP version 6 or IPv6 is created.

  • An example of an IP address version 4 is

IPv4 addresses are divided into several types such as the following

1. Address Unicast

Unicast addresses are specified IPv4 addresses for a network interface that is connected to an IP internetwork. Unicast addresses are used in point-to-point or one-to-one communications. Unicast addresses use classes A, B, and C from the IP address classes mentioned earlier.

In RFC 791 Unicast IP version 4 addresses are divided into several classes, seen from the first octet, as shown in the table. Actually what distinguishes the IP version 4 class is the binary pattern found in the first octet (mainly the high-order bits), but to more easily remember it, it will be faster to remember using decimal representation.

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Class IP Address First octet Template: Br (decimal) First octet Template: Br (binary) Used by.

Address Unicast

Address Unicast


  • Class A 1–126 0xxx xxxx Unicast address for large scale networks.
  • Class B 128–191 1xxx xxxx Unicast address for medium to large scale networks.
  • Class C 192–223 110x xxxx Unicast address for small scale networks.
  • Class D 224–239 1110 xxxx Multicast address (not Unicast address).
  • Class E 240–255 1111 xxxx Reserved, generally used as an address.


2. Broadcast Address

Broadcast Address


Broadcast addresses are IPv4 addresses that are designed to be processed by each IP node in the same network segment. The broadcast address is used in one-to-everyone communication.
The IP version 4 broadcast address is used to deliver “one-for-all” data packages.

If a sender host that wants to send data packets to the destination broadcast address, all nodes contained in the network segment will receive the packet and process it. Unlike a Unicast IP address or multicast IP address, broadcast IP addresses can only be used as destination addresses, so they cannot be used as source addresses.

There are four types of IP broadcast addresses, namely network broadcast, subnet broadcast, all-subnets-directed broadcast, and Limited Broadcast. For each type of broadcast address, the IP broadcast packet will be addressed to the network interface layer by using the broadcast address owned by the network interface technology used. For example, for Ethernet networks and Token Ring, all IP broadcast packages will be sent to the Ethernet broadcast address and Token Ring, namely 0xFF-FF-FF-FF-FF-FF.


a. Network Broadcast

IPv4 network broadcast address is an address formed by setting all host bits to 1 in an address that uses class (classful). An example is, in NetID, the broadcast address is Broadcast network addresses are used to send a packet to all hosts contained in a class-based network. Routers cannot forward packets intended with broadcast network addresses.

b.Subnet broadcast

A broadcast subnet address is an address formed by setting all host bits to 1 in a classless address. For example, in NetID, the broadcast address is The subnet broadcast address is used to send packets to all hosts in a network that has been divided by subnetting, or supernetting. The router cannot forward packets that are addressed with the broadcast subnet address.

The broadcast subnet address is not contained in a network that uses the IP address class, meanwhile, broadcast network addresses are not contained in a network that does not use the IP address class.

c.All-subnets-directed broadcast

This IP address is a broadcast address that is formed by setting all the original network identifier bits that are class based to 1 for a classless network. A network packet addressed to this address will be delivered to all hosts in all subnets that are formed from original class-based network identifers.

An example for this address is for a network identifier, the address of the all-subnets-directed broadcast for it is In other words, this address is the broadcast network address of the original class-based address network identifier. In the example above, address which is the class B address, which by default has a network identifer 16, then the address is

All hosts of a network with an unclassified address will listen and process the packets addressed to this address. RFC 922 requires the IP router to forward the broadcast packet to this address to all subnets in the original class network. Even so, this has not been widely implemented.

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With the number of network identifier addresses that are not classy, ​​this address is no longer relevant to network development. According to RFC 1812, the use of this type of address has been abandoned.


d.Limited broadcast

This address is the address formed by setting all 32 bit IP addresses version 4 to 1 (11111111111111111111111111111111 or This address is used when an IP node must deliver one-to-everyone data on a local network but it does not yet know its network identifier. An example of its use is when the process of configuring an address automatically using Boot Protocol (BOOTP) or Dynamic Host Configuration Protocol (DHCP). For example, with DHCP, a DHCP client must use this address for all traffic that is sent until the DHCP server assigns it an IP address.

All hosts, class-based or classless, will listen and process network packets addressed to this address. Although it looks like using this address, the network packet will be sent to all nodes in all networks, it turns out that this only happens in the local network, and will never be forwarded by the IP router, considering the data packet is limited only in the local network segment . Therefore, this address is referred to as limited broadcast.


3. Multicast Address

Multicast addresses are IPv4 addresses that are designed to be processed by one or several nodes in the same or different network segments. Multicast addresses are used in one-to-many communications.

IP Address Multicast (multicast IP address) is the address used to convey one packet to many recipients. In an intranet that has an IPv4 multicast address, a packet that is addressed to a multicast address will be forwarded by the router to the subnet where there are hosts that are “listening” to the network traffic sent to that multicast address. In this way, multicast addresses are also an efficient way to send data packets from one source to several destinations for several types of communication.

Multicast addresses are defined in RFC 1112.
IPv4 multicast addresses are defined in class D address space, namely, which ranges from to The address prefix (from addresses to cannot be used because it is reserved for use by multicast traffic in the local subnet.


IP address version 6

Unlike IPv4 which only has 32-bit length (the total number of addresses it can reach reaches 4,294,967,296 addresses), IPv6 has a 128-bit length. IPv4, even though the total address reaches 4 billion, in fact there are less than 4 billion addresses, because there are some limitations, so the implementation currently only reaches a few hundred million. IPv6, which has 128-bit length, has a possible total address of up to 2128 = 3.4 x 1038 addresses.

This very large total address aims to provide address space that will not be exhausted (up to several future periods), and form a routing infrastructure that is arranged hierarchically, thereby reducing the complexity of routing processes and routing tables.


Just like IPv4, IPv6 also allows the existence of a DHCP Server as an automatic address manager. If in IPv4 there are dynamic addresses and static addresses, then in IPv6, address configuration using a DHCP Server is called the stateful address configuration, while if the configuration of IPv6 addresses without a DHCP Server is called stateless address configuration.

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Like IPv4 which uses bits at a high level (high-order bits) as network addresses while bits at low levels (low-order bits) as host addresses, in IPv6 similar things also happen. In IPv6, bits at a high level will be used as identification types of IPv6 addresses, called Format Prefix (FP). In IPv6, there is no subnet mask, only Format Prefix.

IPv6 addressing is defined in RFC 2373.


IP Address classes

 Ip Address Classes


Class A

Class A Unicast addresses are given for large scale networks. The highest number of bits in the class A IP address is always set to 0 (zero). The next seven bits – to complete the first octet – will create a network identifier.

The remaining 24 bits (or the last three octets) represent the host identifier. This allows class A to have up to 126 networks, and 16,777,214 hosts per network. Addresses with initial octets 127 are not permitted, because they are used for the Interprocess Communication (IPC) mechanism in the relevant machin.

Class B

Class B Unicast addresses are specific to medium to large scale networks. The first two bits in the first octet class B IP address are always set to binary number 10. The next 14 bits (to complete the first two octets) will create a network identifier. The remaining 16 bits (the last two octets) represent the host identifier. Class B can have 16,384 networks, and 65,534 hosts for each network.

Class C

Class C IP address is used for small networks. The first three bits in the first octet class C address are always set to 110 binary values. The next 21 bits (to complete the first three octets) will form a network identifier. The remaining 8 bits (as the last octet) will represent the host identifier. This allows the creation of a total of 2,097,152 networks, and 254 hosts for each network.

Class D

The class D IP address is provided only for multicast IP addresses, so it is different from the three classes above. The first four bits in class D IP are always set to 1110 binary numbers. The remaining 28 bits are used as addresses that can be used to identify hosts. To more clearly recognize this address, see the IPv4 Multicast Address section.

Class E

The class E IP address is provided as an “experimental” or experimental address and is reserved for future use. The first four bits are always set to 1111 binary numbers. The remaining 28 bits are used as addresses that can be used to identify hosts.

Class Address First octet value Part for Network Identifier Part for Host Identifier Maximum network number Number of hosts in one network maximum.

Class A 1–126 W X.Y.Z 126 16,777,214. Class B 128–191 W.X Y.Z 16,384 65,534. Class C 192–223 W.X.Y Z 2,097,152 254. Class D 224-239 Multicast Multicast IP Address Multicast IP Address Multicast IP Address IP Address. Class E 240-255 Reservedexperiment Reserved; experiment Reserved; experiment Reserved; experiment
Note: The use of the IP address class is now irrelevant, considering that the IP address is no longer using the address class. Internet authority carriers have clearly seen that the addresses divided into classes as above have not been able to meet the current needs, at a time of increasingly widespread Internet use. The new IPv6 address does not currently use classes such as IPv4 addresses. The address made without regard to class is also called classless address

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