Python crawler 07- The process by which a browser sends an HTTP request

1. The client (computer) sends the domain name to the DNS server. The DNS server parses the domain name into an IP address and returns the IP address to the client

2. The client sends a request to the server with the IP address returned by the DNS server, and the service returns the requested page to the client

3.DNS server functions: resolving domain name addresses, because IP addresses are difficult to remember, so the DNS server was born