What is the IP address?

Every computer connected to the Internet (or to any network) has a unique ID, called an IP address (Internet Protocol), consisting of four combinations of numbers (eg, which serves the purpose of identifying our computer from hundreds of millions of devices worldwide.

These numbers, called bytes, can be more than four billion different directions. Each of the four bytes has a specific purpose. The first two groups generally refer to the country and network type (class). This number is a unique identifier in the world together with the time and date can be used, for example, by the authorities, to know the place of origin of a connection.

What is a IP address

To better understand the relationship between IP address and the Internet, first we must know that means the abbreviation TCP (Transmission Control Protocol). A network protocol is like a language, if two people are talking in different languages, ​​if two people speak in different languages, none will understand what the other party says.

With computers, something similar happens, two computers that are physically connected by a network must “speak” the same language for a understands the requirements of the other computer. The TCP protocol standardizes the exchange information flow between computers and enables communication among them. Today, is the most important protocol since is the standard Internet protocol.

The TCP protocol contains the basis for communication of computers within a network. Just as humans, when they want to talk to other humans, they must first search and identify them, the network computers also have to be located and identified. At this point, enter the IP address. The IP address identifies a computer on a given network.

What is a IP address

Across the IP address, we know to what network belongs the computer, and specifically, which is the computer with which we are exchanging information. Briefly, the IP address allows us to know safely the identity of the computer with which we are treating.

How does it work?

The IP addresses can be fixed or dynamic. Currently, fixed IPs are rare, because most times are unsafe. Static IP addresses can be exploited by attackers because the number is always the same. To avoid this, the dynamic IP are used.

Basically, the dynamic IP addresses system rotate the address as follows: a Internet service provider has a X number of available IP addresses. Each time a machine connects to the Internet, the provider assigns a random IP address within a number of IP addresses available. The process used for this distribution more dynamic IPs is the Dynamic Host Configuration Protocol (DHCP).

What is a IP address

To access the URLs, or public IP addresses as we know, (eg http://easytechnow.com/), are used the so-called DNS (Domain Name Server), a data base responsible for the translation of alphanumeric names into IP addresses, essential to the functioning of the Internet as you know today.

Notably that there are IP addresses that are, as a rule, reserved for specific uses. The IP is a number of standard network; how the IP address is used to test a local connection, for network problems diagnoses.

IP address classes

The IP address is a 32 bit number which in practice we always see segmented into four groups of 8 bits each (xxx.xxx.xxx.xxx). Each 8-bit segment varies from 0-255 and are separated by a point.

This division into segments enables IP number classifying IP addresses into 5 classes: A, B, C, D and Y. Each class of address allows a number of networks and computers within these networks.

In networks Class “A” the first 8 bits of the address are used to identify the network, while the other three segments of 8 bits each are used to identify computers.

An IP address class A allows the existence of 126 networks and 16,777,214 computers per network. This is because for Class A networks were reserved by the IANA (Internet Assigned Numbers Authority) IDs “0” to “126”.

Class A IP addresses

What is a IP address

In Class B networks the first two segments of the address are used to identify the network and the last two segments identify computers within these networks.

A class B IP address allows the existence of 16,384 networks and 65,534 computers per network. The ID of these networks begins with “128.0” and goes to “191255”.

Class B IP addresses

What is a IP address

Class C networks use the first three segments of address as a network identifier and only the last segment to identify the computer.

A class C IP address allows the existence of 2,097,152 networks and 254 computers per network. The ID of such network starts at “192.0.1” and ends with “223255255”.

Class C IP addresses

What is a IP address

In Class D networks all segments are used to identify a network and their addresses range from “” to “” and are reserved for so-called multicast.

And class networks as well as class D, used all segments as network IDs and addresses begin with “” and go to “”. Class Y is reserved by IANA for future use.

We must make some considerations about directions Class ID “127” are reserved for Loopback, or for internal testing in networks. All computer equipped with a network adapter has a loopback address, the address which is only seen only by himself and used for internal testing.

Static IP and Dynamic IP

Static IP

The static (or fixed) IP is an IP number permanently assigned to a computer, that is, its IP address does not change, unless such action is carried out manually. For example, the fixed IP are used for some ADSL ISP, which assigned a static IP to some of its customers. Thus, whenever a customer is connected, you use the same IP on the Internet. This practice is becoming less common among access providers, by a number of factors, including security issues.

What is a IP address

Dynamic IP

The dynamic IP, meanwhile, is a number that is assigned to a computer when it connects to the network, number that changes every time the connection is established. For example, suppose you is now connected to Internet with your computer. When you connect morning, you will be assigned a different IP. To better understand, imagine the following scenario: A company has 40 networked computers. Using dynamic IPs, the company provides 40 IP addresses for those computers. Since no IP is fixed, when a computer “comes” in the network, it is assigned an IP of the 40 that is not being used by any other computer.

It is more or less like internet providers work. Every time you connect to the Internet, your ISP gives your computer an IP that is idle. The most widely used method for distributing dynamic IPs is the DHCP (Dynamic Host Configuration Protocol).