IP Address?? What is this...

What is an IP Address?

Today on the INTERNET we always come accross one thing or you might have seen something that says IP address, so umm what the hell is that thing?? You might be curious to know what is it...

The IP Address (or Internet Protocol Address) is an unique address that computing devices such as personal computers, tablets, and smartphones use to identify itself and communicate with other devices in the computer network. Any device connected to the computer network must have an unique IP address within the network. An IP address is analogous to a street address or telephone number in that it is used to uniquely identify an entity.

IP address Standards..

There is a standard of communication which is called an Internet Protocol standard (IP). In laymans terms it is the same as your home address. In order for you to receive snail mail at home the sending party must have your correct mailing address (IP address) in your town (network) or you do not receive bills, pizza coupons or your tax refund. The same is true for all equipment on the internet. Without this specific address, information cannot be received. IP addresses may either be assigned permanently for an Email server/Business server or a permanent home resident or temporarily, from a pool of available addresses (first come first serve) from your Internet Service Provider. A permanent number may not be available in all areas and may cost extra so be sure to ask your ISP.

There are two standards for IP addresses: IP Version 4 (IPv4) and IP Version 6 (IPv6). All computers with IP addresses have an IPv4 address, and many are starting to use the new IPv6 address system as well. Here's what these two address types mean:

>>IPv4 uses 32 binary bits to create a single unique address on the network. An IPv4 address is expressed by four numbers separated by dots. Each number is the decimal (base-10) representation for an eight-digit binary (base-2) number, also called an octet. For example: 216.27.61.137

>>IPv6 uses 128 binary bits to create a single unique address on the network. An IPv6 address is expressed by eight groups of hexadecimal (base-16) numbers separated by colons, as in 2001:cdba:0000:0000:0000:0000:3257:9652. Groups of numbers that contain all zeros are often omitted to save space, leaving a colon separator to mark the gap (as in 2001:cdba::3257:9652).

At the dawn of IPv4 addressing, the Internet was not the large commercial sensation it is today, and most networks were private and closed off from other networks around the world. When the Internet exploded, having only 32 bits to identify a unique Internet address caused people to panic that we'd run out of IP addresses. Under IPv4, there are 232 possible combinations, which offers just under 4.3 billion unique addresses. IPv6 raised that to a panic-relieving 2128 possible addresses. 

How do our computers or devices get ip addresses?

How does your computer get its IP address? An IP address can be either dynamic or static. A static address is one that you configure yourself by editing your computer's network settings. This type of address is rare, and it can create network issues if you use it without a good understanding of TCP/IP. Dynamic addresses are the most common. They're assigned by the Dynamic Host Configuration Protocol (DHCP), a service running on the network. DHCP typically runs on network hardware such as routers or dedicated DHCP servers.

Dynamic IP addresses are issued using a leasing system, meaning that the IP address is only active for a limited time. If the lease expires, the computer will automatically request a new lease. Sometimes, this means the computer will get a new IP address, too, especially if the computer was unplugged from the network between leases. This process is usually transparent to the user unless the computer warns about an IP address conflict on the network (two computers with the same IP address). An address conflict is rare, and today's technology typically fixes the problem automatically.

HOW DHCP ASSIGNS ADDRESSES

When you add a computer to a network, that computer uses a four-step process to get an IP address from DHCP:

Discover -- The computer sends out a broadcast message on the network, hoping to discover a DHCP service provider.

Offer -- Each DHCP provider hears the message, recognizes the unique hardware address of the computer, and sends a message back offering its services to that computer.

Request -- The computer selects a DHCP provider from its offerings and then sends a request to that provider asking for an IP address assignment.

Acknowledge -- The targeted DHCP provider acknowledges the request and issues an IP address to the computer that doesn't match any other IP addresses currently active on the network

IP Classes

 Earlier, you read that IPv4 addresses represent four eight-digit binary numbers. That means that each number could be 00000000 to 11111111 in binary, or 0 to 255 in decimal (base-10). In other words, 0.0.0.0 to 255.255.255.255. However, some numbers in that range are reserved for specific purposes on TCP/IP networks. These reservations are recognized by the authority on TCP/IP addressing, the Internet Assigned Numbers Authority (IANA). Four specific reservations include the following:

• 0.0.0.0 -- This represents the default network, which is the abstract concept of just being connected to a TCP/IP network.
• 255.255.255.255 -- This address is reserved for network broadcasts, or messages that should go to all computers on the network.
• 127.0.0.1 -- This is called the loopback address, meaning your computer's way of identifying itself, whether or not it has an assigned IP address.
• 169.254.0.1 to 169.254.255.254 -- This is the Automatic Private IP Addressing (APIPA) range of addresses assigned automatically when a computer's unsuccessful getting an address from a DHCP server.

The other IP address reservations are for subnet classes. A subnet is a smaller network of computers connected to a larger network through a router. The subnet can have its own address system so computers on the same subnet can communicate quickly without sending data across the larger network. A router on a TCP/IP network, including the Internet, is configured to recognize one or more subnets and route network traffic appropriately. The following are the IP addresses reserved for subnets:

• 10.0.0.0 to 10.255.255.255 -- This falls within the Class A address range of 1.0.0.0 to 127.0.0.0, in which the first bit is 0.
• 172.16.0.0 to 172.31.255.255 -- This falls within the Class B address range of 128.0.0.0 to 191.255.0.0, in which the first two bits are 10.
• 192.168.0.0 to 192.168.255.255 -- This falls within the Class C range of 192.0.0.0 through 223.255.255.0, in which the first three bits are 110.
• Multicast (formerly called Class D) -- The first four bits in the address are 1110, with addresses ranging from 224.0.0.0 to 239.255.255.255.
• Reserved for future/experimental use (formerly called Class E) -- addresses 240.0.0.0 to 254.255.255.254.

The first three (within Classes A, B and C) are those most used in creating subnets. The IANA has outlined specific uses for multicast addresses within Internet Engineering Task Force (IETF) document RFC 5771. However, it hasn't designated a purpose or future plan for Class E addresses since it reserved the block in its 1989 document RFC 1112. Before IPv6, the Internet was filled with debate about whether the IANA should release Class E for general use.

  What is loopback IP address? 

The loopback IP address is the address used to access itself. The IPv4 designated 127.0.0.1 as the loopback address with the 255.0.0.0 subnet mask. A loopback interface is also known as a virtual IP, which does not associate with hardware interface. On Linux systems, the loopback interface is commonly called lo or lo0. The corresponding hostname for this interface is called localhost.

The loopback address is used to test network software without physically installing a Network Interface Card (NIC), and without having to physically connect the machine to a TCP/IP network. A good example of this is to access the web server running on itself by using http://127.0.0.1 or http://localhost.