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An Internet Protocol address (IP Address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. An IP address serves two main functions: host or network interface identification and location addressing.


Classful IP Ranges

Class A IP Address Range0.0.0.0 –
Class B IP Address Range128.0.0.0 –
Class C IP Address Range192.0.0.0 –
Class D IP Address Range224.0.0.0 –
Class E IP Address Range240.0.0.0 –

Private IP address and Public IP address

Based on accessibility, IP addresses are mainly divided in two categories- private IP addresses and public IP addresses.

Private IP addresses

Private IP addresses are the IP addresses which are reserved for local networks and cannot be accessed from a public network such as Internet. Vice versa a public network cannot be accessed from a private IP address.

Following IP ranges are reserved for private IP addresses. to to to

Public IP addresses

Public IP addresses are the IP addresses which are publicly accessible from any public network such as Internet. In order to access a public IP address, we must have to use a public IP address.

Except private IP addresses, all IP addresses of class A, B and C are public IP addresses.

Special IP addresses

Special IP addresses are the IP addresses which are reserved for network testing and troubleshooting. These IP addresses cannot be assigned to an end device or an interface. Following addresses are reserved for special purpose: – This is the first IP address of IP addresses. It represents all networks. to – Reserved for IP protocol testing and troubleshooting. Virtual interfaces such as loopback adaptor use this IP range for addressing. to (Class D): – Reserved for multicast addresses. A multicast address is an address which has multiple recipients. to (Class E): – Reserved for future use. These addresses are not used currently for any purpose. – This is the last IP address of IP addresses. It represents all hosts.

CIDR Subnet Table

Subnet MaskCIDR PrefixTotal IPsUsable IPs*,38416,382,76832,766,53665,534,072131,070,144262,142,288524,286,048,5761,048,574
255.224.0 0/112,097,1522,097,150,194,3044,194,302,388,6088,388,606,777,21616,777,214,554,43233,554,430,108,86467,108,862,217,728134,217,726,435,456268,435,454,870,912536,870,910,073,741,8241,073,741,822,147,483,6482,147,483,646,294,967,2964,294,967,294

IPv6 – What it is?

IPv6 is the newest version of the IP protocol. IPv6 was developed to overcome many deficiencies of IPv4, most notably the problem of IPv4 address exhaustion. Unlike IPv4, which has only about 4.3 billion (2 raised to power 32) available addresses, IPv6 allows for 3.4 × 10 raised to power 38 addresses.

IPv6 features

Here is a list of the most important features of IPv6:

Large address space: IPv6 uses 128-bit addresses, which means that for each person on the Earth there are 48,000,000,000,000,000,000,000,000,000 addresses!

Enhanced security: IPSec (Internet Protocol Security) is built into IPv6 as part of the protocol . This means that two devices can dynamically create a secure tunnel without user intervention.

Header improvements: the packed header used in IPv6 is simpler than the one used in IPv4. The IPv6 header is not protected by a checksum so routers do not need to calculate a checksum for every packet.

No need for NAT: since every device has a globally unique IPv6 address, there is no need for NAT.

Stateless address autoconfiguration: IPv6 devices can automatically configure themselves with an IPv6 address.