Open Port Check Tool (Port Checker Online)
Check if a port is open from the public internet in seconds.
Common ports - click to test
| Port | Protocol | Service |
|---|---|---|
| 80 | HTTP | Web server |
| 443 | HTTPS | Web server (SSL) |
| 554 | RTSP | Camera video stream |
| 8000 | HTTP | Hikvision DVR/NVR |
| 8080 | HTTP | Alternate web / proxy |
| 37777 | TCP | Dahua DVR/NVR |
| 34567 | TCP | XM / Provision / Annke |
| 8443 | HTTPS | HTTPS alternate |
| 22 | SSH | Secure shell |
| 3389 | RDP | Windows Remote Desktop |
| 21 | FTP | File transfer |
How to Check If a Port Is Open from the Internet
Use this open port check tool to check if a port is open on your public IP or hostname. The test runs from an external server and returns open or closed status for each TCP port you enter.
For accurate results, test your public IP or DDNS hostname instead of a local LAN address. If a port shows closed, review port forwarding, firewall rules, and whether the target service is actually listening.
Use it when testing port forwarding for CCTV, DVR, NVR, home servers, SSH, RDP, or web apps. If a result is closed, common causes are NAT/CGNAT, router rules, ISP blocking, local firewall, or no service listening on that port.
What does Open mean in an open port check?
Open means our server reached your target IP and completed a TCP connection on that port. It confirms that the path is reachable from the internet at test time.
Why can a port show Closed even after port forwarding?
Closed can happen if the service is not running, the wrong internal IP is mapped, firewall rules block inbound traffic, or your ISP uses CGNAT.
Do I test my local LAN IP or public IP?
For remote access checks, test your public IP or DDNS hostname. Testing a private LAN IP only validates local network routing, not internet reachability.
Need stable remote access after ports are open? Create a free DDNS hostname ->
Check ports faster on mobile
FastDDNS mobile app includes built-in Port Check, LAN Scan, and WAN IP detection for faster troubleshooting on-site.
