What is DNS? How does a client connect to a server application?

DNS (Domain Name System) is a system that translates domain names (e.g., example.com) into IP addresses understandable by network devices.

When a client wants to connect to a server application, the following happens:

1. The client enters the server's domain name.
2. The client system sends a request to the DNS server to obtain the IP address of this domain.
3. After receiving the IP address, the client establishes a network connection to the server at this address and the required port.
4. Once the connection is established, data exchange occurs between the client and the server.

Example in Go for connecting to a server by domain name:

package main

import (
    "fmt"
    "net"
)

func main() {
    // Resolve domain name to IP
    ips, err := net.LookupIP("example.com")
    if err != nil {
        panic(err)
    }
    fmt.Println("IP addresses:", ips)

    // Connect to the server by IP and port
    conn, err := net.Dial("tcp", "example.com:80")
    if err != nil {
        panic(err)
    }
    defer conn.Close()

    fmt.Println("Successfully connected to the server")
}