How to Monitor Network Activity & Detect Unauthorized Access

Is someone snooping on your network? Is that unknown app secretly sending data to the internet? Every program on your computer that connects to the internet leaves a trail—and you have the right to know what's connecting, when, and where.

In this guide, you'll learn how to monitor all network activity on your Windows PC, detect unauthorized devices on your Wi-Fi, and identify suspicious outgoing connections. Whether you're concerned about privacy, security, or just want to understand what your computer is doing, these tools and techniques will give you full visibility.

This tutorial works for Windows 11, Windows 10, and even older versions like Windows 7. Whether you want to see active internet connections, check who is using your Wi-Fi, or monitor background network traffic, these methods will help you analyze all incoming and outgoing connections.

1. Why You Should Monitor Network Activity

Network monitoring isn't just for IT professionals. Here's why everyday users should care:

2. The Easiest Way: SterJo NetStalker (Free Tool)

SterJo NetStalker is a powerful yet simple network monitoring tool that shows you every connection your computer makes—in real time.

How to Use SterJo NetStalker:

1. Download and run NetStalker (no installation needed for portable version)
2. The main window immediately shows all active connections
3. Right-click any connection to see more details or end the process
4. Enable alerts to get notified of new connections

3. Windows Resource Monitor (Built-in Tool)

Windows comes with a built-in network monitoring tool that many users don't know about.

How to Open Resource Monitor:

1. Press Ctrl + Shift + Esc to open Task Manager
2. Go to the Performance tab
3. Click "Open Resource Monitor" at the bottom
4. Go to the Network tab

What Resource Monitor Shows:

• Processes with Network Activity - All programs currently using the network
• TCP Connections - Active connections with remote addresses
• Listening Ports - Services waiting for incoming connections

4. Using Command Line (Netstat for Advanced Users)

For those comfortable with the command line, netstat provides detailed connection information.

Basic Netstat Commands:

Show all active connections:

netstat -a

Show connections with program names:

netstat -b

(requires administrator privileges)

Show connections with IP addresses and continuous updates:

netstat -n 5

(updates every 5 seconds)

Pro tip: Combine with Find

netstat -b | find "chrome.exe"

Shows only connections from Chrome

5. Detect Intruders on Your Wi-Fi Network

Monitoring your PC is important, but what about other devices on your network? Here's how to see everything connected to your Wi-Fi.

If you also want to recover your saved wireless passwords, see our detailed guide on how to find saved Wi-Fi passwords in Windows.

Method A: SterJo Wireless Network Scanner

SterJo Wireless Network Scanner scans your entire network and lists all connected devices.

• Shows IP and MAC addresses of all devices
• Updates in real-time as devices connect/disconnect

Method B: Router Admin Panel

1. Open browser and enter your router's IP (usually 192.168.0.1 or 192.168.1.1)
2. Log in with admin credentials
3. Look for "Connected Devices," "DHCP Client List," or "Attached Devices"
4. Review the list for unknown devices

What to Do If You Find an Intruder:

1. Change your Wi-Fi password immediately
2. Enable MAC address filtering (optional, advanced)
3. Update router firmware
4. Consider disabling WPS (Wi-Fi Protected Setup)

6. Using Windows Firewall for Monitoring

Windows Firewall can log connections, which is useful for historical analysis.

Enable Firewall Logging:

1. Open Windows Security → Firewall & network protection
2. Click Advanced settings
3. Right-click Windows Defender Firewall → Properties
4. Under Logging, click Customize
5. Enable logging for dropped packets and successful connections

The log file (typically %systemroot%\system32\LogFiles\Firewall\pfirewall.log) shows all connection attempts.

7. How to Identify Suspicious Network Connections

Not every connection is a threat, but here's what to watch for:

🚩 Red Flags:

• Unknown processes making connections (especially with random names)
• Connections to known bad countries (if you don't do business there)
• Processes running from temp folders (C:\Users\name\AppData\Temp\)
• High number of connections from a single unknown process
• Connections on unusual ports (not 80/443 for web traffic)

How to Investigate:

1. Note the program name and path from NetStalker
2. Search online for "[program name] malware" or "[program name] network connection"
3. Check the remote IP address at a site like VirusTotal or whois lookup
4. If suspicious, end the process and scan with antivirus

📚 Related Guides

Take Control of Your Network Security

Your network shouldn't be a mystery. With SterJo NetStalker, you have a window into every connection your computer makes. Regular monitoring helps you spot problems early, whether it's malware, unauthorized access, or just apps you didn't know were "phoning home."

Download SterJo NetStalker Free →

Remember: Security isn't a one-time task. Make network monitoring part of your regular computer maintenance routine.