Open Port Check for Your Server or IP Address

About Open Port Checker

Run an open port check after changing a firewall, a cloud security group or router port forwarding, to see what the internet can reach. Maybe you opened 8080 for a test site, need port 25 reachable for a mail server, or want to be sure MySQL on 3306 and Redis on 6379 aren't exposed. Enter a host name or IP, pick ports from the common list or type your own, up to 10 in all, and click Check ports. On What Is My IP, Check my open ports fills in your own address.

Our server tries every port at once. A port is open when it accepts the connection, with the time shown, closed when nothing is listening, and filtered when a firewall drops the attempt with no reply within 3 seconds. Open ports that shouldn't face the internet, like databases, Redis, Remote Desktop, SMB and Docker, are flagged. Only public addresses can be checked, each target only a limited number of times per hour, and there are no full port scans. Nothing is stored.

How to use Open Port Checker

1. 1
   Enter the host

   Type your server's domain or IP, or start from What Is My IP to test your own connection.

2. 2
   Pick the ports

   Select from the 19 common ports or type others such as 8000 or 9000, up to 10 in all.

3. 3
   Click Check ports

   Our server tries all the chosen ports at the same time and waits up to 3 seconds for each.

4. 4
   Read the table

   Each port shows open, closed or filtered, the time, and a warning if it shouldn't be public.

Why use Cubfile for this

• Up to 10 ports per check

  19 common ports are one click away, and you can add any port from 1 to 65535.

• Open, closed or filtered

  Tells a port with nothing listening apart from one a firewall silently drops.

• Risky ports flagged

  Open databases, Redis, Remote Desktop, SMB, Docker and similar services are marked.

• Copy or CSV

  Keep the results for a security checklist or a ticket to your hosting provider.