What does “open” or “closed” mean?

Open means the service accepts connections. Closed means the port does not respond – either no service is running or a firewall blocks it.

May I scan any server?

No. Only check servers and services you own or have explicit permission for. Internal/private addresses are blocked for security reasons.

Port Check – Check if a Port is Open

Enter a domain or IP address and a port number to check. Tests are performed from Düsseldorf, Germany. Please only test servers you own or have explicit permission to test.

Common ports

Port	Service	Description
21	FTP	File transfer
22	SSH	Secure shell access
25	SMTP	Send email
53	DNS	Domain resolution
80	HTTP	Websites (unencrypted)
110	POP3	Retrieve email
143	IMAP	Email (IMAP)
443	HTTPS	Websites (encrypted)
465	SMTPS	Email (SSL)
587	SMTP (TLS)	Email (TLS)
993	IMAPS	IMAP encrypted
995	POP3S	POP3 encrypted
1433	MSSQL	Microsoft SQL Server
3306	MySQL	MySQL database
3389	RDP	Windows Remote Desktop
5432	PostgreSQL	PostgreSQL database
6379	Redis	Redis cache
8080	HTTP-Alt	Alternative web server
8443	HTTPS-Alt	Alternative HTTPS
27017	MongoDB	MongoDB database

Please only check servers and services that you own or have explicit permission to test. Unauthorized port scanning may be illegal.

My IP Port Check Ping Test SSL Check Blacklist

What is a Port Check?

A port check verifies whether a specific TCP port on a server is reachable from the outside. Ports are like doors to a server – each service listens on a specific port: web servers on port 80 (HTTP) and 443 (HTTPS), mail servers on port 25 (SMTP), SSH on port 22. If a port is closed, either the service is not running or a firewall is blocking access.