IP address, subnet mask, default gateway and DNS server relationship

This article is intended for: computer beginners. This article tries to tell the relevant concepts from the perspective of non-professionals. We welcome professional personnel to supplement and give a helping hand to Xiaobai. In the past, men needed to be able to go to the house to uncover the roof. It was necessary to be able to repair the water pipes. Nowadays men need to install the system and set up the router. The world is changing too fast! Not much nonsense, this article discusses the most common network parameters on the computer: IP address, subnet mask, default gateway and DNS. [IP address] Everyone knows the number of the house number. When the postman uncle sends the letter, he knows where to send it and where to send it. The IP address plays the same role on the computer. Computer A wants to send data (letter) to another computer. At B, the network protocol (postman) sends the data to B based on the IP address. Routers are now very popular network devices, and the computers connected to them (whether wired or wireless) usually have an IP address of 192.168.x.x. For each computer in the network to transmit network data, it must have an IP address that is not duplicated with other computers in the network, that is, a unique address within the network. [Subnet Mask] This seems to be the twin brother of the IP address, or the shadow is more appropriate and always appears together. We know that there are some numbers in the zip code that represent the city, and some IP addresses also represent the network address. This network address requires the subnet mask and IP address as a """ operation. So without the subnet mask, the network protocol will not know which network (city) the data should be sent to. For home networks, the subnet mask is usually 255.255.255.0. 255.255.255.0 and 192.168.1.1 are equal to 192.168.1.0. It can be seen that any number and 255 are equal to the number itself; and 0 is any number with , are equal to 0. [Default Gateway] When sending a message in the past, we usually put the letter into a well-known “mailbox”, where the postman uncle will go there. The default gateway here is like this mailbox, it is an IP address, usually our router LAN address. This means telling us that the computer we are using is sent to this place when sending network data. The “postman” of this place will send the data to our designated destination. [DNS server address] The full name of DNS is Domain Name System, which is the domain name system. This is an IP address, usually specified by the broadband provider. The “Broadband Connection” on the computer, or the WAN port of the router, will be automatically obtained from the broadband provider authentication server. We can also specify it manually, such as the DNS server address of 222.172.200.68. Without a DNS server address, we usually can't get online. This is because the specified server will translate the URL we entered in the browser into an IP address. [Automatic acquisition] So what does automatic acquisition mean in the Internet Protocol IPv4 attribute? That is to tell the computer to obtain parameters such as the IP address from somewhere in the network. This “place” is usually our router. There is a DHCP service in the router that responds to the computer's request and assigns a unique IP address to the network device under it. So, when you find that you can't get online, the first thing you should do is to check if your network connection has the correct IP address and so on.