What is IP Address and How to find this?

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Definition of IP address and why all computers and devices need one

An IP address (internet protocol address) is a numerical representation that uniquely identifies a specific interface on the network.

Addresses in IPv4 are 32-bits long. This allows for a maximum of 4,294,967,296 (2³²) unique addresses. Addresses in IPv6 are 128-bits, which allows for 3.4 x 10³⁸ (2¹²⁸) unique addresses.

The total usable address pool of both versions is reduced by various reserved addresses and other considerations.

IP addresses are binary numbers but are typically expressed in decimal form (IPv4) or hexadecimal form (IPv6) to make reading and using them easier for humans.

The Internet Protocol (IP)

IP stands for Internet Protocol and describes a set of standards and requirements for creating and transmitting data packets, or datagrams, across networks. The Internet Protocol (IP) is part of the Internet layer of the Internet protocol suite. In the OSI model, IP would be considered part of the network layer. IP is traditionally used in conjunction with a higher-level protocol, most notably TCP. The IP standard is governed by RFC 791.

How IP works

IP is designed to work over a dynamic network. This means that IP must work without a central directory or monitor and that it cannot rely upon specific links or nodes existing. IP is a connectionless protocol that is datagram-oriented., so each packet must contain the source IP address, destination IP address, and other data in the header to be successfully delivered.

Combined, these factors make IP an unreliable, best-effort delivery protocol. Error correction is handled by upper-level protocols instead. These protocols include TCP, which is a connection-oriented protocol, and UDP, which is a connectionless protocol.

Most internet traffic is TCP/IP.

IP versions

There are two versions of IP in use today, IPv4 and IPv6. The original IPv4 protocol is still used today on both the internet and many corporate networks. However, the IPv4 protocol only allowed for 2³² addresses. This, coupled with how addresses were allocated, led to a situation where there would not be enough unique addresses for all devices connected to the internet.

IPv6 was developed by the Internet Engineering Task Force (IETF) and was formalized in 1998. This upgrade substantially increased the available address space and allowed for 2¹²⁸ addresses. In addition, there were changes to improve the efficiency of IP packet headers, as well as improvements to routing and security.

IPv4 addresses

IPv4 addresses are actually 32-bit binary numbers, consisting of the two subaddresses (identifiers) mentioned above which, respectively, identify the network and the host to the network, with an imaginary boundary separating the two. An IP address is, as such, generally shown as 4 octets of numbers from 0-255 represented in decimal form instead of binary form.

For example, the address 168.212.226.204 represents the 32-bit binary number 10101000.11010100.11100010.11001100.

The binary number is important because that will determine which class of a network, the IP address belongs to.

An IPv4 address is typically expressed in dotted-decimal notation, with every eight bits (octet) represented by a number from one to 255, each separated by a dot. An example IPv4 address would look like this:

192.168.17.43

 

IPv4 addresses are composed of two parts. The first numbers in the address specify the network, while the latter numbers specify the specific host. A subnet mask specifies which part of an address is the network part, and which part addresses the specific host.

A packet with a destination address that is not on the same network as the source address will be forwarded or routed, to the appropriate network. Once on the correct network, the host part of the address determines which interface the packet gets delivered to.

Subnet masks

A single IP address identifies both a network and a unique interface on that network. A subnet mask can also be written in dotted-decimal notation and determines where the network part of an IP address ends, and the host portion of the address begins.

When expressed in binary, any bit set to one means the corresponding bit in the IP address is part of the network address. All the bits set to zero marks the corresponding bits in the IP address as part of the host address.

The bits marking the subnet mask must be consecutive ones. Most subnet masks start with 255. and continue on until the network mask ends. The class C subnet mask would be 255.255.255.0.

Overview: IP address classes and bit-wise representations

Class A
  0.  0.  0.  0 = 00000000.00000000.00000000.00000000
127.255.255.255 = 01111111.11111111.11111111.11111111
                  0nnnnnnn.HHHHHHHH.HHHHHHHH.HHHHHHHH

Class B
128.  0.  0.  0 = 10000000.00000000.00000000.00000000
191.255.255.255 = 10111111.11111111.11111111.11111111
                  10nnnnnn.nnnnnnnn.HHHHHHHH.HHHHHHHH

Class C
192.  0.  0.  0 = 11000000.00000000.00000000.00000000
223.255.255.255 = 11011111.11111111.11111111.11111111
                  110nnnnn.nnnnnnnn.nnnnnnnn.HHHHHHHH

Class D
224.  0.  0.  0 = 11100000.00000000.00000000.00000000
239.255.255.255 = 11101111.11111111.11111111.11111111
                  1110XXXX.XXXXXXXX.XXXXXXXX.XXXXXXXX

Class E
240.  0.  0.  0 = 11110000.00000000.00000000.00000000
255.255.255.255 = 11111111.11111111.11111111.11111111
                  1111XXXX.XXXXXXXX.XXXXXXXX.XXXXXXXX

Private addresses

Within the address space, certain networks are reserved for private networks. Packets from these networks are not routed across the public internet. This provides a way for private networks to use internal IP addresses without interfering with other networks. The private networks are

10.0.0.1 - 10.255.255.255

172.16.0.0 - 172.31.255.255

192.168.0.0 - 192.168.255.255

 

Special addresses

Certain IPv4 addresses are set aside for specific uses:

127.0.0.0	The loopback address (the host’s own interface)
224.0.0.0	IP Multicast
255.255.255.255	Broadcast (sent to all interfaces on a network)

 

IPv4 address exhaustion

The original IPv4 specification was designed for the DARPA network that would eventually become the internet. Originally a test network, no one contemplated how many addresses might be needed in the future. At the time, the 2³² addresses (4.3 billion) were certainly considered sufficient. However, over time, it became apparent that as currently implemented, the IPv4 address space would not be big enough for a worldwide internet with numerous connected devices per person. The last top-level address blocks were allocated in 2011. 

IPv6 addresses

To avoid the seemingly reoccurring issue in technology, where a specification’s limitation seems more than sufficient at the time, but inevitably becomes too small, the designers of IPv6 created an enormous address space for IPv6. The address size was increased from 32 bits in IPv4 to 128 bits in IPv6.

The IPv6 has a theoretical limit of 3.4 x 10³⁸ addresses. That’s over 340 undecillion addresses, which is reportedly enough addresses to assign one to every single atom on the surface of the earth.

IPv6 addresses are represented by eight sets of four hexadecimal digits, and each set of numbers is separated by a colon. An example IPv6 address would look like this:

2DAB:FFFF:0000:3EAE:01AA:00FF:DD72:2C4A

IPv6 address abbreviation

With IPv6 addresses being so long, there are conventions to allow for their abbreviation. First, leading zeros from any one group of numbers may be eliminated. For example, :0033: can be written as 33:

Second, any consecutive sections of zeros can be represented by a double colon. This may be done only once at any address. The number of sections removed using this abbreviation can be determined as the number required to bring the address back up to eight sections. For example, 2DAB::DD72:2C4A would need to have five sections of zeroes added back in place of the double colon.

(2DAB:0000:0000:0000:0000:0000:DD72:2C4A)

The loopback address

0000:0000:0000:0000:0000:0000:0000:0001

may be abbreviated as :1.

IPv6 private addresses

Like in IPv4 certain address blocks are reserved for private networks. These addresses are not routed over the public internet. In IPv6, private addresses are called Unique Local Addresses (ULA). Addresses from the FC00:: /7 block are ignored and not routed by default.

How To Find IP Address Using Python Code?

# python
	import socket
	hostname = socket.gethostname()
	IPAddr = socket.gethostbyname(hostname)
	print(IPAddr)