Domain name resolution is a very important link in the Internet. Its existence allows us to access websites through simple and easy-to-remember domain names without having to remember complex IP addresses. So, why do we need domain name resolution?

First of all, domain name resolution can make it easier for us to remember and use Internet resources. In the early days of the Internet, people needed to remember a string of numerical IP addresses to access websites, which was very difficult for most people. With domain name resolution, we only need to remember a simple domain name to easily access the corresponding website. For example, we only need to enter "www.google.com" to enter the Google search engine without remembering its corresponding IP address.

Secondly, domain name resolution can improve the reliability and flexibility of the website. In the Internet, IP addresses change dynamically, especially for large websites, the IP addresses of their servers may change frequently. If we access the website directly through the IP address, once the server's IP address changes, we will no longer be able to access the website. Through domain name resolution, we only need to update the mapping relationship between domain names and IP addresses to achieve seamless switching to a new server.

In addition, domain name resolution can also improve network security. There are a large number of malware and hacker attacks on the Internet. They may resolve legitimate domain names to malicious IP addresses by tampering with DNS servers, thereby conducting illegal activities such as phishing and hijacking user information. To prevent this from happening, we can improve network security by using a trusted DNS server for domain name resolution.

Finally, domain name resolution can also achieve load balancing and failover. For large websites, in order to cope with high concurrent access and ensure the stability of the website, multiple servers are usually used for load balancing. Through domain name resolution, we can resolve a domain name to the IP addresses of multiple servers, thereby achieving request distribution and load balancing. When a server fails, we only need to remove its corresponding IP address from the domain name resolution to achieve failover.