IP Address Introduction

What is an IP address

The IP address (Internet Protocol address) is also referred to as the inter-network addresses and internetwork addresses. IP address refers to the Internet Protocol address (English: Internet Protocol address, and also translated as Internet Protocol addresses), is the abbreviation of IP address. IP address is a unified address format provided by the IP protocol, which allocates a logical address for each network on the Internet and each host to block differences in physical addresses.

IP address is the Network Layer address scheme in the TCP/IP protocol stack, and the IP address is a logical identifier used for network devices.

To give a life example , if I want to send a letter to friends in Hubei, you need to know the address of friends, such as: xx province xx xx district xx Road xx, I just know this address, and in the letter, the destination on the envelope to write this address on it.

If you put it on a network and one network device communicates with another network device, you need to know the destination IP address.

format of IP address

The TCP/IP address is set to 32bit, the value range is 2 of 32, a total of "4294967296" IP address.

The IP address is divided into four segments, each section 8bit, if converted into decimal, the range of the value of each paragraph is from 0~255

The computer will generally translate the IP into binary, and our individual users, the binary is not sensitive, and changed to use dotted decimal to represent IP, divided into four segments, separated by a decimal point, each section of the value range of 256, from 0~255 (2 8)

For example, "192.168.1.1", "202.100.98.3", is the dotted decimal point of the IP address representation method.

IP Address Classification

The IP addresses, which were divided into 5 categories, were as follows:

Class A IP: From 0.0.0.0–127.255.255.255, a total of 16,777,216 IP

Class B IP: From 128.0.0.0–191.255.255.255, a total of 65,536 IP

Class C IP: From 192.0.0.0–223.255.255.255, a total of 256 IP

Class D IP: From 224.0.0.0–239.255.255.255

Class E IP: From 2240.0.0.0–255.255.255.255

It is important to note that :

A, B, c these three types of IP address, is for users to use the

Class D IP address is a multicast protocol used

Class E IP addresses are reserved for use by scientific institutions and are now unused, turning to IPv6

Public IP address (public IP)

To build an enterprise-class network, you need to go to the "telecom operator ISP" to apply for a broadband Internet access, while the ISP will also assign us one or more IP addresses, these IP addresses can be used in our enterprise intranet, these ISPs assigned to our IP, is the public IP.

Public addresses, or public addresses, are the responsibility of the Internet NIC (Internet Network Information Center Internet Information Center). These IP addresses are assigned to organizations that register and request an Internet NIC. Through it direct access to the Internet, it is WAN Fan Fanne .

scope of public IP address :

Public IP for Class A:

1.0.0.0~9.255.255.255

11.0.0.0~126.255.255.255

Public IP for Class B:

128.0.0.0~172.15.255.255

172.32.0.0~191.255.255.255

Public IP in Class C:

192.0.0.0~192.168.255.255

192.169.0.0~223.255.255.255

Private IP address (private network IP)

In our enterprise or family, the IP used for local area network is usually used as private IP.

Private addresses (private address, also known as the network address) belong to the non-registered address, specifically for internal use of the organization, it is within the scope of the LAN, private IP banned in the Internet, where the ISP connects users, the traffic from the private IP will be blocked and discarded. Frankly, private IP cannot be connected directly to the Internet .

If a computer inside the enterprise wants to access the Internet, it is necessary to use NAT technology on the enterprise boundary to turn the private network IP into a public IP for normal internet access. For details, please see " Communication between Intranet and extranet ".

range of Private IP addresses :

a class private IP address:

10.0.0.0~10.255.255.255

b class private IP address:

172.16.0.0~172.31.255.255

c class private IP address:

192.168.0.0~192.168.255.255

Reference: DAVID_XTD

IP Address Introduction