What is a port scanner?
A port scanner is a tool that checks which network ports on a host accept connections. Every service exposed to the internet — a website, mail server, database, or remote-desktop endpoint — listens on a specific TCP port. By probing those ports, you can see what a host exposes to the outside world. This scanner performs a standard TCP connect check against a curated list of the most common ports and reports each as open, closed, or unavailable. Results reflect what is reachable from our servers, which may differ from your own network.
Why scan your ports?
- Security auditing — find ports that are open by mistake and could become an entry point for attackers.
- Firewall testing — confirm that only the ports you intend to expose are actually reachable.
- Troubleshooting — diagnose connectivity problems when a service is unreachable.
- Service discovery — quickly see which services (web, mail, database, remote access) a host is running.
How to check open ports
- Enter the domain name or IP address you want to check.
- Press “Scan ports” and wait a few seconds for the results.
- Review the table — open ports are highlighted in green; “unavailable” means the port did not respond.
Responsible use
Only scan hosts that you own or have explicit permission to test. Scanning systems without authorization may violate computer-misuse laws in your jurisdiction. This tool is rate-limited, logs requests, and is provided for legitimate diagnostic and security-auditing purposes only, without warranty of any kind.