Open Port Checker & Exposure Scan
See your connection the way an attacker on the internet does. Check one port to test port forwarding, or scan your own IP address for the services that should never be reachable from outside: Remote Desktop, file sharing, databases, NAS and CCTV admin pages.
- Your own IP only
- 35 risky services
- Results in seconds
Exposure scan
Checks your IP address (…) for 35 services that attackers look for. It takes about 3 seconds.
What the results mean
- Open: something answered, so anyone on the internet can reach it.
- Closed: your router or device actively refused the connection. Nothing is listening there.
- Filtered: no answer at all, usually a firewall silently dropping it. That's the safest result.
- We only test TCP from our UK server, and only your own address. Some services (like many VPNs) use UDP, which this doesn't test.
If something risky is open
- Remove the port forwarding rule in your router, and turn off UPnP if you don't need it: it lets devices open ports by themselves.
- For remote access, use a VPN or a remote access service with multi-factor authentication, never a port forward to Remote Desktop.
- Cyber Essentials requires the firewall to block unnecessary inbound connections, and any allowed service to be justified and documented.
- Can't open a port at all? Your provider may use carrier-grade NAT (common with mobile, Starlink and some full-fibre providers), which shares one public address between many customers. Ask them for a public or static IP.