Open Port Scanner

Tests whether the ports on an IP address are reachable from the internet. The target IP defaults to your IP; you can enter a different public IP that you own. Pick a category below or add custom ports (max 20).

Target IP (editable)
Auto-detected — this IP will be used for the scan.

Select Ports to Test

0 / 100 ports selected
Comma-separated port numbers (1–65535). Max 20 ports. Duplicates are removed automatically.
Selected: 0 ports

Scanning…

Testing the selected ports.

Scan Results

How to interpret the results?

  • CLOSED — the port is not reachable from the internet. The ideal state.
  • OPEN — reachable from the internet. If high-risk ports such as 3306 (MySQL), 6379 (Redis), 27017 (MongoDB), 5900 (VNC), 3389 (RDP), 445 (SMB) are open, malicious scanners will find the target within 1-5 minutes.
  • For most home users every port should be closed. An open port means port forwarding is configured on your router/modem.
  • If you run a server, only 22 (SSH) and 80/443 (web) should be open; database ports should never be exposed.

Ethical use

  • Only scan IP addresses that you own or have explicit permission to scan. Unauthorized port scanning is illegal in many countries.
  • Private/reserved ranges (192.168.x.x, 10.x.x.x, 127.0.0.1, ::1, fe80::) cannot be scanned for safety reasons — these addresses are not reachable from the internet anyway.
  • Scanning is rate-limited: 10 per minute, 100 per hour requests.

Free Open Port Scanner for IPv4 Addresses

Our online port scanner checks whether TCP ports on a public IPv4 address are reachable from the internet. It is designed for home users verifying their firewall, sysadmins auditing exposed services, and security researchers with explicit permission.

What is an open port?

An open port means a service (SSH, RDP, MySQL, web server, etc.) accepts inbound connections from the internet. Unnecessary open ports are a common entry point for automated attacks and botnet scans.

Scan your own IP

Enter your public IP to see what attackers see. Most residential connections should show all ports closed unless you deliberately forwarded a service on your router.

Rate limits & ethics

Scans are rate-limited to protect our infrastructure. Only scan IPs you own or have written permission to test — unauthorized scanning may be illegal in your jurisdiction.

Port Scanner — FAQ

Quick answers to the most common questions about this tool.

What is an open port?

A TCP/UDP port that accepts incoming connections from the internet. Each open port is a potential entry point — most home users should have all ports closed.

Why does my router show ports as "stealth"?

"Stealth" usually means the firewall drops packets without replying, so attackers can't even tell the IP is alive. "Closed" means the port replies with RST. Both are safe.

Should I close port 22 (SSH)?

Only if you do not need remote access. If you need SSH, do not disable it — instead enforce key-based auth, use a non-default port and lock it to specific source IPs.

Is port scanning legal?

Scanning your own IPs and authorised systems is legal. Scanning third-party IPs without permission may violate computer-misuse laws in your country. We log nothing, but you are responsible for compliance.