What is the standard IP address format?

1: What is an IP address? What is the standard ip address format?

IP address refers to the Internet Protocol Address (English: Internet Protocol Address, also translated as Internet Protocol Address), which is the abbreviation of IP Address. The IP address is a unified address format provided by the IP protocol. It assigns a logical address to each network and each host on the Internet to shield the differences in physical addresses. [Recommended article: What does IP mean】

The IP address consists of four decimal integers separated by decimal points. In fact, an IP address is a 32-bit binary number. Each 8 bits can be represented by a decimal integer number.

2: There are several IP address formats:

1. Class A address.

A Class A IP address means that among the four segments of the IP address, the first segment is the network number, and the remaining three segments are the local computer numbers. If the IP address is represented in binary, the Class A IP address consists of a 1-byte network address and a 3-byte host address. The highest bit of the network address must be "0". The length of the network identifier in a Class A IP address is 8 bits, and the length of the host identifier is 24 bits. The number of Class A network addresses is small and can be used for large networks with more than 16 million hosts. Class A IP address The address range is 1.0.0.0 to 126.255.255.255 (binary representation is: 00000001 00000000 00000000 00000001 - 01111111 11111111 11111111 11111111). The last one is the broadcast address. The subnet mask of a Class A IP address is 255.0.0.0, and the maximum number of hosts supported by each network is 256 to the third power -2 = 16777214.

2. Class B address.

A Class B IP address means that among the four numbers in the IP address, the first two numbers are network numbers. If the IP address is represented in binary, the Class B IP address consists of a 2-byte network address and a 2-byte host address. The highest bit of the network address must be "10". The length of the network identifier in the Class B IP address is 16 bits, and the length of the host identifier is 16 bits. Class B network addresses are suitable for medium-sized networks, and each network can accommodate more than 60,000 computers. Class B IP address range 128.0.0.0-191.255.255.255 (binary representation: 10000000 00000000 00000000 00000001----10111111 11111111 11111111 11111110). The last one is the broadcast address. The subnet mask of Class B IP address is 255.255.0.0, and the maximum number of hosts supported by each network is 256 to the power of 2 - 2 = 65534 units

3. Class C address.

IP address picture A Class C IP address means that among the four numbers in the IP address, the first three numbers are the network number, and the remaining number is the number of the local computer. If the IP address is represented in binary, the Class C IP address consists of a 3-byte network address and a 1-byte host address. The highest bit of the network address must be "110". The length of the network identifier in a Class C IP address is 24 bits, and the length of the host identifier is 8 bits. Class C network addresses have a larger number and are suitable for small-scale local area networks. Each network can only contain a maximum of 254 computers. Class C IP address range 192.0.0.0-223.255.255.255 (binary representation is: 11000000 00000000 00000000 00000001 - 11011111 11111111 11111111 11111110). The subnet mask of Class C IP address is 255.255.255.0, and the maximum number of hosts supported by each network is 256-2=254

4. Special URL.

1. The addresses starting with "lll0" are called multicast addresses. Therefore, any IP address whose first byte is greater than 223 and less than 240 (range 224.0.0.1-239.255.255.254) is a multicast address.

2. The address where each byte is 0 ("0.0.0.0") corresponds to the current host.

3. The IP address in which each byte in the IP address is 1 ("255.255.255.255") is the broadcast address of the current subnet.

4. All Class E IP addresses starting with "llll0" in the IP address are reserved for future and experimental use.

5. The IP address cannot start with decimal "127". The numbers 127.0.0.1 to 127.255.255.255 in this type of address are used for loop testing. For example: 127.0.0.1 can represent the local IP address. Use "http://127.0.0.1" can test the web server configured on this machine.

6. The first 6-bit group of the network ID cannot be set to all "0". All "0" indicates the local network.

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