Tools / Port checker / 1433
Is port 1433 open?
Port 1433 is Microsoft SQL Server. Enter your server below to test it from Dallas, Amsterdam and London.
What port 1433 is used for
Default port for Microsoft SQL Server database connections. Named instances often use dynamic ports, found through the SQL Browser service on UDP 1434.
Should port 1433 be open?
Should not face the internet directly. One of the most scanned ports on the internet. Keep it behind a firewall, VPN or SSH tunnel; never expose the sa account.
How to open port 1433
Ubuntu or Debian with ufw, allowing only your own address (replace 203.0.113.10):
sudo ufw allow from 203.0.113.10 to any port 1433 proto tcp
Rocky, Alma or CentOS with firewalld:
sudo firewall-cmd --permanent --add-port=1433/tcp && sudo firewall-cmd --reload
Windows Server, in PowerShell as administrator:
New-NetFirewallRule -DisplayName "Port 1433" -Direction Inbound -Protocol TCP -LocalPort 1433 -Action Allow
Then check that the service listens on all addresses, not only 127.0.0.1, and test again above.
Check another port
Run your service on a PrivateByte server: a firewall you control and every port yours to open.