Open Port Scanner
Scan your public IP for dangerous open ports — RDP, SMB, and more. See what attackers see before they do.
Scans 15 common ports: FTP, SSH, Telnet, SMTP, HTTP, POP3, RPC, HTTPS, SMB, MSSQL, MySQL, RDP, VNC, HTTP-Alt, HTTPS-Alt.
The scan runs from our server against your public IP. May take up to 25 seconds.
Using a VPN or Tor? The scan will test the VPN server's or Tor exit node's IP — not your home connection. Disable it first for an accurate result.
How the Scan Works
Unlike browser-based tools that are limited by security restrictions, this scanner runs server-side: our server attempts a TCP connection to each port on your public IP and records whether the port is open, closed, or filtered by a firewall.
Three possible results for each port:
| ⚠ OPEN | A service is listening and accepted the connection. The port is reachable from the internet. |
| ✓ CLOSED | The port responded but refused the connection. No service running, but the port is reachable. |
| FILTERED | No response within the timeout. A firewall is likely dropping packets silently. |
The scan only covers your public-facing IP — the address the internet sees. Devices behind your router are not individually exposed unless you have port forwarding rules configured.
Why Open Ports Are a Risk
Every open port is a potential entry point. Automated scanners operated by attackers continuously sweep the entire IPv4 address space, probing for open ports on every public IP. When they find one, they attempt known exploits and credential attacks within minutes.
RDP (port 3389) is the #1 ransomware entry point in the US. On today's internet, an exposed RDP port is like leaving your front door wide open in a bad neighborhood — attackers will find it and start knocking within minutes. US small businesses and home offices running Windows Remote Desktop directly on the internet are primary targets.
The risk varies by port. A web server intentionally running HTTP/HTTPS on ports 80 and 443 is expected. But an exposed database port (3306, 1433) or remote desktop port (3389, 5900) on a home or small business connection is almost always a misconfiguration — and a serious one.
What to Do If a Dangerous Port Is Open
If you don't know why a port is open, it shouldn't be. Disable the service or block the port in your firewall. On Windows, check Services and Windows Defender Firewall. On a router, check port forwarding rules.
If you need RDP or SSH access to your machine, don't expose the port directly. Put it behind a VPN — connect to the VPN first, then use remote access. This removes the service from public view entirely.
If you must keep a port open, limit access to specific trusted IP addresses. For example, allow RDP only from your office IP. Most modern routers and cloud firewalls (like AWS or Azure) support IP allowlisting.
If closing or hiding the port isn't possible, move the service to a non-standard port and ensure you're using complex, unique credentials with account lockout enabled to block brute-force attempts. While this won't stop a determined attacker, it drastically reduces the success of automated botnets and stops most "spray-and-pray" attacks. Security through obscurity is not enough — a weak password is still a back door.
The Verdict: Closed Should Be Your Default
For most home users and small businesses, no ports should be open unless you are explicitly running a public service. If your scan shows RDP, SMB, Telnet, or any database port as open — close it immediately.
Final step: check your router's UPnP and port forwarding settings, your firewall rules, and any remote access software you may have installed. Disable UPnP on your router to prevent devices from automatically opening ports without your knowledge. After making changes, re-run this scan to verify your security.
Also Check Your Email for Breaches →