(1) Know the IP address

On the network, the target host can be found as long as the IP address is used. Therefore, if you want to attack a network host, the first to find the host domain name or IP address, the number of domain names and IP is not one by one corresponding, a domain name to multiple IP addresses. Readers who want to know more about the content of the network protocol can refer to the author's other articles. The IP address is actually a way of addressing, just like our phone number. But different IP protocols assign a 32-bit (bit) address to each connection on the Internet and also become an international protocol address.

According to the provisions of TCP/IP (Transport Control protocol/internet Protocol, Transmission Protocol/Network Protocol) protocol, IP address is represented by binary, each IP address is 32 bits long, (about bit, byte, word length, character, KB,GB , the TB distinction please see the author in the "Microcomputer principle" classification of another article, in simple terms 1 bytes = 8 bits). For example: A binary representation of the IP address is 0000100100000000000000000000000001, such a long address, the human brain is very difficult to deal with, in order to facilitate the use of the IP address is often written in decimal form, the middle of the use of symbols "." The decimal address is divided into equal 4 parts, in the form of XXX.XXX.XXX.XXX, we are most familiar with the 127.0.0.1, that is, the native address.

How are the IP addresses divided? Each interface in the Internet has a unique IP address corresponding to it, the address is not a flat form of space address, but has a certain structure, in general, the IP address can be divided into the following 5 categories, as shown in:

(1) Know the IP address