SterJo NetStalker — Free PC Security & Network Monitoring Software

Protect your confidential information with SterJo NetStalker, a free Windows application that monitors all network connections to your PC. It alerts you to both authorized and unauthorized access, helping maintain your PC security and network protection.

• Monitor all TCP and UDP connections on your PC
• Detect unauthorized access instantly
• Track and log all network activity
• Portable and free for all Windows versions

Free Computer Protection

SterJo NetStalker is designed for comprehensive PC protection. It monitors TCP and UDP connections, analyzes all running processes, and alerts you about suspicious activity. It acts like a firewall, but focuses on monitoring and logging network traffic rather than blocking by default.

All active connections are displayed with detailed information, including local and remote IP addresses, ports, and their current status. You can block processes that violate rules defined in the Policy tab. Logs and history allow you to track all network activity for later review.

How SterJo NetStalker Works

SterJo NetStalker works as a network monitoring software that protects your PC from unwanted internet activity. It monitors all TCP and UDP connections initiated by applications and services running on your system.

After launching, the software scans all running processes and displays them under the Activity tab, showing local and remote IP addresses, ports, and connection status. A status bar continuously updates to show ongoing network activity.

If any suspicious process is detected that could threaten your PC security, a pop-up window alerts you. You can choose to quit or block the process, or allow it if it’s safe. The software intelligently enforces rules defined in the Policy tab, ensuring only authorized traffic passes.

The Policy tab allows you to add new rules or modify existing ones. Pre-configured rules help you get started quickly. The Security menu provides modes to allow, filter, block, or pause traffic according to your preferences.

All network activity is logged. The Log tab saves connection events, and the History tab records actions you perform. This allows you to review and track activity to maintain maximum security.

Download & Installation

Download the installer or portable version to start monitoring your PC immediately. SterJo NetStalker supports both 32-bit and 64-bit versions of Windows XP through Windows 11.

Current Version: 1.4

Download Portable Version

TCP Status Table

• CLOSED: No connection exists.
• LISTENING: Waiting for a connection request from a remote end-point.
• SYN_SENT: Connection request sent to remote end-point.
• SYN_RCVD: Acknowledged connection request from remote end-point.
• ESTABLISHED: Connection is active.
• FIN_WAIT1: Active close initiated by local end-point.
• CLOSE_WAIT: Local end-point acknowledged termination request.
• FIN_WAIT2: Waiting for remote termination acknowledgment.
• LAST_ACK: Passive close initiated, awaiting acknowledgment.
• CLOSING: Waiting for termination acknowledgment before TIME_WAIT.
• TIME_WAIT: Ensures remote end-point received acknowledgment before closing.

Version history

Version 1.4: Minor bug fixes and improvements.

Version 1.3: Minor changes and bug fixes.

Version 1.2: Fixed flickering while refreshing connections.

Version 1.1: Minor updates.

Version 1.0: First public release.

Frequently Asked Questions

What does SterJo NetStalker do?

— SterJo NetStalker monitors all TCP and UDP connections to your PC, detects unauthorized access, and alerts you to suspicious activity to maintain your PC security and network protection.

Is SterJo NetStalker free and portable?

— Yes. SterJo NetStalker is completely free to download and offers a portable version that can run from a USB drive without installation.

Does SterJo NetStalker automatically block internet traffic?

— No. It monitors traffic and alerts you. You can create rules in the Policy tab to accept, block, or filter connections manually.

Which Windows versions are supported?

— SterJo NetStalker supports Windows XP, Vista, 7, 8, 10, and 11 (both 32-bit and 64-bit versions).

How do I block a suspicious process?

— Use the Policy tab to create a rule for the process. You can choose to block, allow, or filter connections based on your preferences.

Can I use SterJo NetStalker alongside my existing firewall?

— Yes. SterJo NetStalker is a monitoring tool and works alongside standard firewalls without conflicts.

Does SterJo NetStalker run in the background automatically?

— Yes. Once launched, it continuously monitors network activity until you close the application.

How do I update SterJo NetStalker?

— Updates can be downloaded from the official website. Simply replace the old version with the new installer or use the updated portable version.

Is my data safe with SterJo NetStalker?

— Yes. The software only monitors connections locally on your PC and does not collect or send personal data.

Can I export the logs?

— Yes. Logs and history can be saved and reviewed later to track all network activity for better security management.