Open port check: is your RDP open to the internet?

Attackers scan the whole internet for open Remote Desktop, file sharing and database ports every day. See in seconds what they can see of your network.

What the result means

• Open: anybody on the internet can reach this service and try passwords or exploits on it. For Remote Desktop (3389), file sharing (445), VNC (5900), WinRM (5985) and databases (1433, 3306, 5432) that is almost never a good idea.
• Closed: the port did not answer from the internet. Good.
• Web (80 / 443) and mail (25) open is normal if you run a web or mail server on purpose.
• The check sees the address your network uses on the internet. Behind a router, an open port means the router forwards it to a computer inside.

How to close an open port with Windows' own tools

1. Remove the router's port forwarding for the service, if nobody needs to reach it from outside.
2. Limit the Windows Firewall rule to the addresses that really need it: wf.msc › Inbound Rules › the rule › Scope › Remote IP address.
3. Use a VPN or a Remote Desktop Gateway for remote access instead of opening RDP directly.

The catch: you need to know which rule is behind which port, keep the address lists up to date, and check again after every change. A one-time check like this one tells you nothing about tomorrow.

See this at any time, from inside: Coinetic

This page is a one-time look from outside. Coinetic shows you the same and more at any time, on every Windows Server and PC, and fixes it:

• Every open port, always in view: the Open Ports page shows each listening port, the program behind it and who can reach it through the firewall. The security check runs in the background and tells you when something new is open to the internet.
• Coinetic closes it, or makes it invisible forever or until you unlock it from your phone. One click limits a port to your own network and VPN. With Device approval, RDP stays invisible until you tap Unlock on your phone, then it opens only for your phone's address and closes again by itself. How it works.
• A port you keep open on purpose is watched: every connection to it is recorded with address, owner and country.
• Attackers are banned automatically: port scanners and password guessers are locked out by a Windows Firewall rule after the limit you set.
• Your AI security analyst (Pro + AI): right-click a port and choose Ask AI, e.g. “Why is port 3389 open, and should it be?”. It answers in plain words, with what to do on this machine.

More guides: all Coinetic guides.

Frequently asked

Can I check another address or a server somewhere else?

No. To prevent misuse, the check only ever tests the address you are visiting from. To check a Server, open this page on that Server, or install Coinetic there: it shows its open ports at any time.

Port 3389 is open. Am I hacked?

Not necessarily, but you are being tried. Open RDP ports get password guesses within minutes of going online. Look for Event ID 4625 in the Security log (how to read it) and close the port or limit it to known addresses.

Everything shows closed, but I use RDP from outside. Why?

You may be visiting from a different network than the one you connect to (for example your phone's mobile network), or a VPN is in between. Run the check from a computer on the network you want to test.

Is the check safe?

We only try to open a connection to each port and close it at once. Nothing is sent to the service and nothing is stored except how many ports were open.