For troubleshooting purposes, I would like to be able to check if a client can connect to a SQL Server instance, independent of the application that possibly can't connect to the SQL Server.
Is there an easy way (that means, not having to install 3rd party software) to do this using the default Windows system tools? Perhaps using scripts or network applications?
If the server is using TCP/IP, then the simple way is to just telnet to the SQL Server port and see if it connects. By default, that's port 1433, so this should work:
telnet servername 1433
That will probably be appropriate in most cases.
If it's using a different port, or dynamic ports (common with a named instance), then you'll need to determine which port it's currently listening on. Check SQL Server configuration manager to see if it's a specific port, or dynamic ports. If it's using dynamic ports, then as long as you don't have multiple instances on the server, netstat -abn is probably the simplest way to find what it's using. Otherwise, dig through the Windows event log or the SQL Server error log for a message indicating which port is in use by the instance.
If SQL Server is using Named Pipes, then I believe if you're able to access shares on the machine, you have adequate network connectivity. This article says you can go further and try connecting to the IPC$ share:
http://msdn.microsoft.com/en-us/library/aa275787%28v=sql.80%29.aspx
net use \\servername\IPC$
That's written for SQL Server 2000, but I don't imagine this aspect has changed much, if at all.
A simple test method for SQL connectivity is to create an empty text file, with a file extension of "UDL". You can create it in Notepad. And it can have any name. I use "TestSQL.UDL"
Save it on the desktop of a windows PC and double click it.
A "Data Link Properties" dialog box will pop up where you can enter the IP address of the SQL server and also a SQL username and password.
Click the "Test Connection" button to see if you can connect.
Provided you have the Microsoft.SqlServer.Smo assembly in your GAC on the local machine, this can be easily done with PowerShell:
[Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.Smo') | Out-Null
$server = New-Object Microsoft.SqlServer.Management.Smo.Server("YourSqlServerName")
# do a simple operation to see if you can get data
Try {
$server.Version | Out-Null
Write-Host "SQL Server connection successful!!!"
}
Catch [System.Exception] {
Write-Host "Error connecting to SQL Server..."
}
There are so many ways to check connectivity - I got tired of googling every time I needed to check SQL connectivity from Windows, macOS, linux; to help with that, I created a docker image to test SQL connectivity. It's very (very) basic and I will probably improve this overtime, but hopefully it saves people time. Ok, so to test SQL connectivity simply run this command:
docker run -it ssaadi/test-sql-conn
It will ask you for host name, instance, port etc and then will try to connect and run select @@servername or display error if it fails.
The script is created in python and uses pymssql for sql connection -- the very very basic source code can be found here: https://github.com/sameersaadi/test-sql-conn
