Difference between external IP and internal IP
1. The relationship between the internal and external networks: Using reality as an analogy, the public network address is similar to the public address, Luohu Building, No. 504, Lane 2, Luohu 1st Road, Luohu District, Shenzhen---the public network address, this address is the only one in the city. Room 502, Floor 3A, Block B, Luohu Building----Intranet address---------Any building can have Room 502, Floor 3A, Block B. If you assign an address to each house, the address in the city will be confusing and confusing. not enough.
2. Classification of IP addresses: Class A, B, and C networks continue to use reality as a metaphor for the concepts of room, floor, area, and seat in the above. Now the "intranet" of Luohu Building is an example, how can I mark 1,000 houses. Class A address: provide the house number in sequence from 0001 to 1000, and provide a house number directly for each room. Class B address: divided by layer, 1st floor is 01XX, 2nd floor is 02XX. The number of each layer is limited. Class C address: Divide by district level: First, divide by location, such as the south area of east area, area B of area A, and then assign the number according to the floor: such as A101, B502. According to the IP address specification, there are many blocks divided by C-type addresses, so each block has fewer house numbers, and A-type addresses are not divided into blocks, so there can be more house numbers.
3. The public IP applied for is a specific IP address, similar to the house number on the municipal road. For example, No. 504 Luohu Road, this No. 504 Luohu Road is the IP issued to you. But since you are on Luohu Road, I will not send you No. 504, Jiabin Road. The router connecting to the public network is the gate of a certain address (for example, Luohu Building, No. 504, Luohu Road). The data finds this gate. After entering, you can see how the building is divided and find the room you want to enter.