Open Port Checker
Check which ports are open on a server: web, mail, FTP, SSH, databases or your own list.
About the Open Port Checker
Every service on a server listens on a port: websites on 80 and 443, email on 25, 465, 587 and 993, SSH on 22, MySQL on 3306. An open port checker tells you whether a service can be reached from the internet – useful when email or a control panel will not connect, when you have just opened a port in your firewall, or when you want to be sure that nothing sensitive is exposed.
Choose a group of ports or enter your own (up to 20) and this tool connects to each one from our server. Open means the server accepted the connection, closed means it refused, and filtered means a firewall did not answer at all. It also warns you when database or remote-access ports such as 3306, 5432, 6379 or 3389 are open to everyone – these are among the first things attackers scan for.
Frequently asked questions
What is the difference between closed and filtered?
Closed means the server answered and said nothing is listening on that port. Filtered means there was no answer, usually because a firewall silently drops the connection.
Why does port 25 show as filtered?
Many hosting and cloud providers block outgoing connections to port 25 to stop spam, so our server may not be able to reach it even when it is open. Mail clients normally use 465 or 587 instead.
Is it safe to have port 3306 open?
Usually not. Databases should only accept connections from your own server or a private network. Close the port in your firewall or bind the database to localhost.