About intranet IP addresses and public IP addresses in the network

Public network IP and intranet IP

First, let's take a look at the IP address Division:

Class A address:0.0.0.0------127.255.255.255

Where 127.255.255.255 is the broadcast address and cannot be assigned

Class B Address:128.0.0.0------191.255.255.255

Class C Address:192.0.0.0------223.255.255.255

Class D Address:224.0.0.0-----239.255.255.255

Class E Address:240.0.0.0------255.255.255

   

If you want to see how much IP you have on your machine, you can view it like this

Start --- run, enter cmd--- enter ipconfig/all in the dialog box that pops up, and return to the list .

One of them: theIP address is the IP of your machine. Try

1, LAN private address is (private address or intranet address):

Class A address: 10.0.0.0------10.255.255.255

Because the class a address network number is 7 bits, the host number is a four-bit, so the network segment is relatively small (long has 2 of 7 Square -2 network), But the number of hosts per network segment is large ( 2 per 2 pcseach ), so A -class address is typically used for large companies or manufacturers .

Class B Address: 172.16.0.0----172.31.255.255

Because the network number of class B addresses is the number of digits, the host number is

Class C Address: 192.168.0.0---192.168.255.255

Because the network number of class B address is the number of bits, the host number is 8 bits,

Note: These addresses can be reused on different LANs, butIP cannot be duplicated within the same LAN.

2. Special address is:

Class A system loopback address: 127.0.0.0-----127.255.255.255

Each computer has a local loopback interface address, which is 127.0.0.1, which is used to test whether the TCP/IP stack of this machine is properly installed.

Class B Address: 168.192.0.0---168.192.255.255

Class B reserved Address:169.254.0.0----169.254.255.255

Class D Address: 224.0.0.0-----239.255.255.255

Class E Address: 240.0.0.0-----255.255.255.255

Second, the public network address:

(0.0.0.0----223.255.255.255) address, except for the above "LAN private Address" and "special address" is a public address.

     we already know ip address includes both public and private (private) types, public network ip The address is also known as a globally routable ip address, which is internet The ip address used in the is mainly isp one or several c class address; Is the principle or the same

Frankly speaking, the public network IP is recognized on the Internet, private IP is not known on the Internet, only you know. Public network IP is generally assigned by network operators. Includes fixed and auto-assigned. General large units are private line access, is used fixed IP, small units or household, mostly ADSL This automatic allocation of IP . General one into the dot use an IP! Usually is N lan IP, through the router with a public network IP to the Internet. The router is responsible for packet forwarding

Third, the intranet address (also known as private network address, private address, LAN private address):

Intranet is the local area network, the most intuitive is like internet cafes, the company's internal computer with the switch,HUB, routing connected together. Then through the light brazing. The cat is connected to the INTERNET .

Intranet IP is the international allocation of IP , set aside a portion of IP, not used on Internat , for internal LAN, and so on, although the same function, but not in used on Internat. is a non-registered address and is intended for use within an organization.

The computer in the intranetNAT(Network address Translation) protocol, accessed through a public gatewayInternet。 On the Internet, there is a callNATThe technology is used to convert the address, is to solve the public networkIPThe problem is not enough to be born, for example, your hostIPAddress is192.168.12.1, this is a privateIPThis oneIPis not to be routed, that is, the Internet is not recognized, this time, you goISP, such as telecommunications, to apply for a public networkIPLike what200.176.23.4, this time, you are on the router to make aNAT, Put your privateIPand your public network.IPMake a map, you can go online, but now we generally use thenaptIs the technique of port mapping, but theIPAddress planning,
a computer on the intranet can send connection requests to other computers on the Internet , but other computers on the Internet cannot send connection requests to computers in the intranet.

Intranet IP is generally private IP
There are usually 3 kinds:
10.x.x.x
172.16.x.x---172.31.x.x
192.168.x.x
The private IP of intranet is to save the IP address, on the other hand, protect the security of internal information!
You said 192.168.1.2, belong to the intranet IP, but you in the Internet bar, the actual you also have an external network IP, you net bar inside all the computer outside the network appears to be the same (external network) IP
Extranet IP identifies your address throughout the Internet
The intranet IP identifies your address on your local area network!

About intranet IP addresses and public IP addresses in the network