Netscan
To create a network scan program in Go, you need to create a few files: main.go for the main logic, and optionally, a netscan.go file for the network scanning 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 netscan
cd netscan
go mod init github.com/username/netscan
Step 2: Create the netscan.go File
Create a netscanmod/netscan.go file to handle the network scanning functionality.
// netscan.go
package netscan
import (
"fmt"
"net"
"time"
)
// ScanPort checks if a port is open on a given host.
func ScanPort(protocol, hostname string, port int) bool {
address := fmt.Sprintf("%s:%d", hostname, port)
conn, err := net.DialTimeout(protocol, address, time.Second)
if err != nil {
return false
}
conn.Close()
return true
}
// ScanHost scans a range of ports on a given host.
func ScanHost(hostname string, startPort, endPort int) {
for port := startPort; port <= endPort; port++ {
if ScanPort("tcp", hostname, port) {
fmt.Printf("Port %d is open\n", port)
}
}
}
Step 3: Create the main.go File
Create a main.go file to use the network scanning functionality.
// main.go
package main
import (
"fmt"
"os"
"strconv"
netscan "github.com/username/netscan/netscanmod"
)
func main() {
if len(os.Args) != 4 {
fmt.Println("Usage: netscan <hostname> <startPort> <endPort>")
os.Exit(1)
}
hostname := os.Args[1]
startPort, err := strconv.Atoi(os.Args[2])
if err != nil {
fmt.Printf("Invalid start port: %v\n", err)
os.Exit(1)
}
endPort, err := strconv.Atoi(os.Args[3])
if err != nil {
fmt.Printf("Invalid end port: %v\n", err)
os.Exit(1)
}
netscan.ScanHost(hostname, startPort, endPort)
}
Step 4: Run the Program
Run the program using the go run command.
go run main.go example.com 1 1024
This will scan ports 1 to 1024 on the specified hostname and output the open ports.
Last modified: 08 January 2025