Access to the SQL Server database engine is achieved using one of three protocols.
By default, SQL Server accepts connections using the Shared Memory protocol.
It may interest you to know that SQL Server supports two others - Named Pipes and TCP/IP.
If you don’t, you will get an error like this.
[08S01] The TCP/IP connection to the host localhost, port 1433 has failed. Error: "Connection refused: no further information. Verify the connection properties. Make sure that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port. Make sure that TCP connections to the port are not blocked by a firewall.".
SELECT net_transport FROM sys.dm_exec_connections WHERE session_id = @@SPID;
If you are using SQL Server 2019 you can enable TCP as follows:
- Hit Win + R, to open the run command
Paste the following in the dialog
With the dialog looking as below, press enter.
You should see the following:
Expand this node to see the protocols configured.
You will see that TCP/IP is disabled. Double click to open the configuration.
Set enabled to Yes then press OK to accept the changes.
- Finally, restart the SQL Server service so that this change is accepted.
From an Administrative Powershell window, run the following command.
Restart-Service MSSQLSERVER -force
Once done you can try again to connect.
You should now be able to connect successfully.
If you’re using a different version of SQL Server, these are the names of the MMC consoles to launch.
|Version||Snap In Name|
|SQL Server 2019||SQLServerManager15.msc|
|SQL Server 2017||SQLServerManager14.msc|
|SQL Server 2016||SQLServerManager13.msc|
|SQL Server 2014 (12.x)||SQLServerManager12.msc|
|SQL Server 2012 (11.x)||SQLServerManager11.msc|