Composition IP address:
By a 32-bit number sequence consisting of a sequence of binary digits, decimal point, the use of 4 points is divided into 32 segments, each 8-bit binary digital number, but the binary numbers are hard to remember, thus converted to decimal, That is dotted decimal
Classification IP address:
Composition IP address { <network number> <host number> }
Class A: 1.0.0.0 to 126.255.255.255 is assigned to the main host computer and a large network with a large number of small number of local area network
Class B: 128.0.0.0 to 191.255.255.255 are generally used for large international companies and government agencies
Class C: 192.0.0.0 to 223.255.255.255 for general small companies and research institutes school network
Class D: 244.0.0.0 to 339.255.255.255 for special purposes, also known as a broadcast address
Class E: 240.0.0.0 to 247.255.255.255 escrow
Special Address:
Native loopback address 127.0.0.1
0.0.0.0 Network Address
255.255.255.255 broadcast address
Let's introduce the concept and the difference between public ip and private ip of:
- Public IP: Public IP, via INTERNIC the unified planning of IP, IP can even have this on the Internet;
- Private IP: Private IP or reserved IP, can not be directly connected to the Internet IP, mainly for the host online planning in the local area network.
Early in the planning of IPv4 IP worried that there will be insufficient, and in order to deal with some internal corporate network settings, so there will be a private IP (Private IP) is produced.
Private IP respectively at A, B, C each of which three Class retention period as a private IP network, that is:
- Class A：10.0.0.0 - 10.255.255.255
- Class B：172.16.0.0 - 172.31.255.255
- Class C：192.168.0.0 - 192.168.255.255
Since these three sections of IP Class is reserved for future use, so as not directly connected to the Internet with the above.
Generally speaking, we are unable to find Ipcofig public network ip, most of the time, you use the ipconfig found generally just beginning with 172. b-class private Ip, or in private Ip 192.168 at the beginning of class c simple. say, s private ip has several limitations underneath:
- Private IP routing information can not be spread outside (there is only the internal network);
- Private IP as a source or destination address of the packet can not be transferred through the Internet (otherwise the network will chaos);
- Reference record on private IP (such as DNS), can only be limited to the internal network to use (the same principle it)
This private IP what good is it? Because of his private foreign direct routing can not provide information, so, your internal network will not be directly above Internet Cracker attacked! However, you will not be able to directly access to private IP!
