Free Online Port Checker
Scan common services or test a custom TCP port to verify firewall rules and server status.
TCP Port Scanning FAQ & Guide
What is a network port?
Ports are virtual communication endpoints used by transport layer protocols (TCP and UDP) to route internet traffic to specific software applications or services running on a host server. Each server IP has 65,535 TCP and UDP ports.
What are the most common server ports?
Port 22 (SSH): Secure Shell for remote server terminal access.
Port 80 (HTTP) & 443 (HTTPS): Standard ports for cleartext and encrypted website traffic.
Port 21 (FTP): File Transfer Protocol for uploading files.
Port 3306 (MySQL) & 5432 (PostgreSQL): Relational database connection ports.
Port 25 (SMTP) & 587 (Submission): Simple Mail Transfer Protocol for email routing.
Why check if a port is open?
Auditing ports helps developers confirm that background daemons (such as database engines or custom web servers) are reachable by authorized clients. It also ensures sensitive administration ports are closed to the public internet to prevent brute-force intrusion attempts.
What does a closed or timed-out port mean?
A Closed status means the host server is reachable but actively rejects connection attempts because the service is stopped. A Timed Out status means the server is silently dropping request packets, typically due to firewall security rules.