Simple network monitor

network_monitor.py

import platform
import subprocess
import time
from datetime import datetime

def check_internet():
    try:
        # Use nslookup to perform a DNS lookup for google.com
        result = subprocess.run(["nslookup", "-type=ns", "google.com", "8.8.8.8"], capture_output=True, text=True, timeout=5)
        return result.returncode == 0
    except subprocess.TimeoutExpired:
        console_message("DNS lookup timed out")
        return False
    except subprocess.CalledProcessError as e:
        console_message(f"Error during DNS lookup: {e}")
        return False
    except Exception as e:
        console_message(f"Unexpected error during DNS lookup: {e}")
        return False

def run_command(command):
    try:
        output = subprocess.check_output(command, stderr=subprocess.STDOUT, universal_newlines=True)
        return output.strip()
    except subprocess.CalledProcessError as e:
        return f"Error: {e.output.strip()}"

def troubleshoot():
    os_name = platform.system().lower()
    results = []

    if os_name == "windows":
        results.append(("IP Configuration", run_command(["ipconfig", "/all"])))
        results.append(("Connection Test", run_command(["curl", "-I", "-s", "-m", "5", f"http://1.1.1.1"])))
        results.append(("Trace Route", run_command(["tracert", "google.com"])))
    elif os_name == "darwin":  # macOS
        results.append(("IP Configuration", run_command(["ifconfig"])))
        results.append(("Connection Test", run_command(["curl", "-I", "--connect-timeout", "5", f"http://1.1.1.1"])))
        results.append(("Trace Route", run_command(["traceroute", "google.com"])))
    else:
        results.append("Unsupported OS")
    return results

def log_message(message, log_file):
    timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    log_entry = f"{timestamp} - {message}"
    print(log_entry)
    with open(log_file, "a+") as f:
        f.write(log_entry + "\n")

def console_message(message):
    timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    log_entry = f"{timestamp} - {message}"
    print(log_entry)


def main():
    log_file = "network_monitor.log"
    console_message("Network monitoring started. Press Ctrl+C to stop.")
    
    last_status = True
    while True:
        current_status = check_internet()
        if current_status != last_status:
            if current_status:
                log_message("Internet connection restored.", log_file)
            else:
                log_message("Internet connection lost. Running troubleshooting...", log_file)
                troubleshooting_results = troubleshoot()
                for title, result in troubleshooting_results:
                    log_message(f"{title}:\n{result}", log_file)
                    log_message("-" * 50, log_file)

        last_status = current_status
        time.sleep(5)  # Check every 5 seconds

if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        console_message("Monitoring stopped.")

Threw this together with help from an AI coding assistant when I needed to track intermittent failures on my home network. (Turned out the cable modem was overheating inside a cabinet.)

I'm sure there are better ways to do this, but it works. Feel free to add improvement suggestions in the comments.