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IP ADDRESS

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.

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Classful IP Ranges

CLASSIP ADDRESS RANGE
Class A IP Address Range0.0.0.0 – 127.255.255.255
Class B IP Address Range128.0.0.0 – 191.255.255.255
Class C IP Address Range192.0.0.0 – 223.255.255.255
Class D IP Address Range224.0.0.0 – 239.255.255.255
Class E IP Address Range240.0.0.0 – 255.255.255.255

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.

10.0.0.0 to 10.255.255.255

172.16.0.0 to 172.31.255.255

192.168.0.0 to 192.168.255.255

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: –

0.0.0.0:- This is the first IP address of IP addresses. It represents all networks.

127.0.0.0 to 127.255.255.255: – Reserved for IP protocol testing and troubleshooting. Virtual interfaces such as loopback adaptor use this IP range for addressing.

224.0.0.0 to 239.255.255.255 (Class D): – Reserved for multicast addresses. A multicast address is an address which has multiple recipients.

240.0.0.0 to 255.255.255.255 (Class E): – Reserved for future use. These addresses are not used currently for any purpose.

255.255.255.255 – This is the last IP address of IP addresses. It represents all hosts.

CIDR Subnet Table

Subnet MaskCIDR PrefixTotal IPsUsable IPs
255.255.255.255/3211
255.255.255.254/3122*
255.255.255.252/3042
255.255.255.248/2986
255.255.255.240/281614
255.255.255.224/273230
255.255.255.192/266462
255.255.255.128/25128126
255.255.255.0/24256254
255.255.254.0/23512510
255.255.252.0/2210241022
255.255.248.0/2120482046
255.255.240.0/2040964094
255.255.224.0/1981928190
255.255.192.0/1816,38416,382
255.255.128.0/1732,76832,766
255.255.0.0/1665,53665,534
255.254.0.0/15131,072131,070
255.252.0.0/14262,144262,142
255.248.0.0/13524,288524,286
255.240.0.0/121,048,5761,048,574
255.224.0 0/112,097,1522,097,150
255.192.0.0/104,194,3044,194,302
255.128.0.0/98,388,6088,388,606
255.0.0.0/816,777,21616,777,214
254.0.0.0/733,554,43233,554,430
252.0.0.0/667,108,86467,108,862
248.0.0.0/5134,217,728134,217,726
240.0.0.0/4268,435,456268,435,454
224.0.0.0/3536,870,912536,870,910
192.0.0.0/21,073,741,8241,073,741,822
128.0.0.0/12,147,483,6482,147,483,646
0.0.0.0/04,294,967,2964,294,967,294

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.