Tool Port Check
Is a port open from the internet?
Enter a host and pick a port to see whether a connection can be made to it from outside, which helps when a firewall or service is in question.
About the Port Check
A port is a numbered door on a server that a particular service listens on: 80 and 443 for websites, 25 and 587 for sending email, 993 for IMAP, 22 for SSH and 3306 for MySQL. If a firewall blocks a port or the service has stopped, connections to it fail.
This tool tries to open a connection to the port you choose from our server on the public internet, so it shows what the outside world sees rather than what works inside your own network. It is limited to well-known ports and one port per check.
Frequently asked questions
Enter the host name or IP address, choose the port and press Check. "Open" means a connection was accepted; "Closed or filtered" means it was refused or no answer came back.
Usually a firewall is blocking it, either on the server itself, at the hosting provider or on the router in front of it. Some internet providers also block port 25 for outgoing mail.
Generally no. Ports such as 3306 (MySQL) and 5432 (PostgreSQL) should only accept connections from trusted addresses, not from the whole internet.