Dig/nslookup
To create a dig/nslookup program in Go, you need to create a few files: main.go for the main logic, and optionally, a dnslookup.go file for the DNS lookup functionality. Here is a step-by-step guide:
Step 1: Initialize the Go Module
First, create a new directory for your project and initialize the Go module.
mkdir dnslookup
cd dnslookup
go mod init github.com/username/dnslookup
Step 2: Create the dnslookup.go File
Create a dnslookupmod/dnslookup.go file to handle the DNS lookup functionality.
// dnslookup.go
package dnslookup
import (
"net"
)
// DNSLookup performs a DNS lookup for the given domain and returns the IP addresses.
func DNSLookup(domain string) ([]string, error) {
ips, err := net.LookupIP(domain)
if err != nil {
return nil, err
}
var result []string
for _, ip := range ips {
result = append(result, ip.String())
}
return result, nil
}
Step 3: Create the main.go File
Create a main.go file to use the DNS lookup functionality.
// main.go
package main
import (
"fmt"
"os"
dnslookup "github.com/username/dnslookup/dnslookupmod"
)
func main() {
if len(os.Args) != 2 {
fmt.Println("Usage: dnslookup <domain>")
os.Exit(1)
}
domain := os.Args[1]
ips, err := dnslookup.DNSLookup(domain)
if err != nil {
fmt.Printf("DNS lookup for %s failed: %v\n", domain, err)
os.Exit(1)
}
fmt.Printf("DNS lookup result for %s:\n", domain)
for _, ip := range ips {
fmt.Println(ip)
}
}
Step 4: Run the Program
Run the program using the go run command.
go run main.go example.com
This will output the IP addresses for the specified domain.
Last modified: 08 January 2025