Before explaining what is the difference between public and private IP is worth mentioning is an IP address. An IP address (Internet Protocol address) is a numerical code used to uniquely identify a device (host) connected to a network the Internet (public) or a local area network (private).
This address is used by the adapter host (a computer, a computer, a mobile device, a Web TV) that uses the Internet Protocol (IP) as a method of communication to identify and to exchange information.
Put simply an IP address can be considered as a phone number that serves to communicate between computers and other devices on the Internet and within a home or office LAN.
PUBLIC IP ADDRESS AND PRIVATE IP ADDRESS
For the need to limit the use of IP addresses (the number of which is limited) and to prevent an IP address of a host present within a LAN (Local Area Network) can be confused with the IP address of a host connected to the Internet were created public IP addresses and private IP addresses.
We try to understand what is the difference between public and private IP.
WHAT IS THE PUBLIC IP
The ‘ public IP address is an IP address visible and accessible to all hosts on the Internet. The public IP is assigned by your ISP (Internet Service Provider), the Internet service provider, and is used to enable communication between devices that do not belong to the same LAN and to access the Internet.
Each host connected to the Internet must have its own Public IP address must be different from that of any other host connected to the World Wide Web . For the duration of the connection, worldwide, will not exist another host with a public IP equal.
The public IP can be considered as a fingerprint is used to uniquely identify a device connected to the Internet (→ IP address: difference between static dynamic public and private ).
Globally, the public IP addresses are assigned by ‘ ICANN (the Internet Corporation for Assigned Names and Numbers).
PUBLIC STATIC IP AND DYNAMIC PUBLIC IP
Depending on the type of service provided by the ISP network a user can have a dynamic public IP address or a static public IP.
The ‘ dynamic public IP can vary every time we connect to the Internet and is used in most cases for domestic users.
The ‘ public static IP instead never changes and is almost always used in the enterprise.
WHAT IS PRIVATE IP
The ‘ private IP address is used to uniquely identify a device on the same LAN.
While the public IP identifies a host connected to the Internet worldwide, the private IP identifies the device within the same local area network.
The private IP addresses can not be used for the connection to the Internet and are not visible outside of a local network .
The private IP addresses can be used within a LAN by anyone , without the need of requesting the assignment to ‘ ICANN.
The private IP addresses are not used by the router for routing data in the transport network but needed to talk hosts on the LAN.
When a host on a LAN (using a private IP) must connect to the Internet (where you need a public IP) is used to NAT (network address translation), a technique that allows you to “map” more private IP addresses on a single public IP address visible outside the LAN and then used to access the Internet.
PRIVATE IP STATIC AND DYNAMIC PRIVATE IP
Even a private IP can be static or dynamic as it can be assigned automatically or manually.
If we choose to use an address dynamic private IP assignment will be performed by the router automatically using DHCP (Dynamic Host Configuration Protocol).
If we choose to use an address private static IP assignment must be done manually by entering the code number directly on the device.
The private IP addresses are common to all routers on the market. The same private IP address can be used over and over on the condition that they are in different LANs.
DIFFERENCE BETWEEN PUBLIC AND PRIVATE IP
The first major difference between the public and private IP is that a public IP address identifies a computer or other device in the global Internet and then to join him. A private IP address instead makes visible the computer or device within the same network.
In the case of IP private computer you will therefore not be reached directly from the Internet unless the network operator does not assign a public IP.
The difference between private and public IP is also about safety.
The level of security of an Internet connection made using a private IP to be much higher than in the case of a public IP. This is because access to the network will be protected not only by the tools of computer security (antivirus and personal firewall) but also by devices of the private network provider (firewalls, proxies, routers).