Category Archives: SQL SERVER 2016

Configure Windows Firewall for Database Engine Access

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Configure Windows Firewall for Database Engine Access

This topic describes how to configure a Windows firewall for Database Engine access in SQL Server 2016 by using SQL Server Configuration Manager. Firewall systems help prevent unauthorized access to computer resources. To access an instance of the SQL Server Database Engine through a firewall, you must configure the firewall on the computer running SQL Server to allow access.

For more information about the default Windows firewall settings, and a description of the TCP ports that affect the Database Engine, Analysis Services, Reporting Services, and Integration Services, see Configure the Windows Firewall to Allow SQL Server Access. There are many firewall systems available. For information specific to your system, see the firewall documentation.

The principal steps to allow access are:

  1. Configure the Database Engine to use a specific TCP/IP port. The default instance of the Database Engine uses port 1433, but that can be changed. The port used by the Database Engine is listed in the SQL Server error log. Instances of SQL Server Express, SQL Server Compact, and named instances of the Database Engine use dynamic ports. To configure these instances to use a specific port, see Configure a Server to Listen on a Specific TCP Port (SQL Server Configuration Manager).
  2. Configure the firewall to allow access to that port for authorized users or computers.Note
    The SQL Server Browser service lets users connect to instances of the Database Engine that are not listening on port 1433, without knowing the port number. To use SQL Server Browser, you must open UDP port 1434. To promote the most secure environment, leave the SQL Server Browser service stopped, and configure clients to connect using the port number.Note
    By default, Microsoft Windows enables the Windows Firewall, which closes port 1433 to prevent Internet computers from connecting to a default instance of SQL Server on your computer. Connections to the default instance using TCP/IP are not possible unless you reopen port 1433. The basic steps to configure the Windows firewall are provided in the following procedures. For more information, see the Windows documentation.

As an alternative to configuring SQL Server to listen on a fixed port and opening the port, you can list the SQL Server executable (Sqlservr.exe) as an exception to the blocked programs. Use this method when you want to continue to use dynamic ports. Only one instance of SQL Server can be accessed in this way.

In This Topic

Before You Begin

Security 

Opening ports in your firewall can leave your server exposed to malicious attacks. Make sure that you understand firewall systems before you open ports. For more information, see Security Considerations for a SQL Server Installation

Using SQL Server Configuration Manager

The following procedures configure the Windows Firewall by using the Windows Firewall with Advanced Security Microsoft Management Console (MMC) snap-in. The Windows Firewall with Advanced Security only configures the current profile. For more information about the Windows Firewall with Advanced Security, see Configure the Windows Firewall to Allow SQL Server Access

To open a port in the Windows firewall for TCP access

  1. On the Start menu, click Run, type WF.msc, and then click OK.
  2. In the Windows Firewall with Advanced Security, in the left pane, right-click Inbound Rules, and then click New Rule in the action pane.
  3. In the Rule Type dialog box, select Port, and then click Next.
  4. In the Protocol and Ports dialog box, select TCP. Select Specific local ports, and then type the port number of the instance of the Database Engine, such as 1433 for the default instance. Click Next.
  5. In the Action dialog box, select Allow the connection, and then click Next.
  6. In the Profile dialog box, select any profiles that describe the computer connection environment when you want to connect to the Database Engine, and then click Next.
  7. In the Name dialog box, type a name and description for this rule, and then click Finish.

To open access to SQL Server when using dynamic ports

  1. On the Start menu, click Run, type WF.msc, and then click OK.
  2. In the Windows Firewall with Advanced Security, in the left pane, right-click Inbound Rules, and then click New Rule in the action pane.
  3. In the Rule Type dialog box, select Program, and then click Next.
  4. In the Program dialog box, select This program path. Click Browse, and navigate to the instance of SQL Server that you want to access through the firewall, and then click Open. By default, SQL Server is at C:Program FilesMicrosoft SQL ServerMSSQL13.MSSQLSERVERMSSQLBinnSqlservr.exe. Click Next.
  5. In the Action dialog box, select Allow the connection, and then click Next.
  6. In the Profile dialog box, select any profiles that describe the computer connection environment when you want to connect to the Database Engine, and then click Next.
  7. In the Name dialog box, type a name and description for this rule, and then click Finish.

See Also
How to: Configure Firewall Settings (Azure SQL Database)

Parallel Query Processing

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    • SQL Server provides parallel queries processing to optimize query execution and index operations for computers that have more than one microprocessor (CPU). Because SQL Server can perform a query or index operation in parallel by using several operating system threads, the operation can be completed quickly and efficiently.
    • During query optimization, SQL Server looks for queries or index operations that might benefit from parallel execution.
    • For these queries, SQL Server inserts exchange operators into the query execution plan to prepare the query for parallel execution.
    • After exchange operators are inserted, the result is a parallel-query execution plan.
    • A parallel query processing execution plan can use more than one thread. A serial execution plan, used by a nonparallel query, uses only one thread for its execution. The actual number of threads used by a parallel query is determined at query plan execution initialization and is determined by the complexity of the plan and the degree of parallelism.
    • Degree of parallelism determines the maximum number of CPUs that are being used; it does not mean the number of threads that are being used. The degree of parallelism value is set at the server level and can be modified by using the sp_configure system stored procedure.
    • You can override this value for individual query or index statements by specifying the MAXDOP query hint or MAXDOP index option.
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    The SQL Server query optimizer does not use a parallel execution plan for a query if any one of the following conditions is true:

    • The serial execution cost of the query is not high enough to consider an alternative, parallel execution plan.
    • A serial execution plan is considered faster than any possible parallel execution plan for the particular query.
    • A serial execution plan is considered faster than any possible parallel execution plan for the particular query.
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    Configure the max degree of parallelism option

    • In Object Explorer, right-click a server and select Properties.
    • Click the Advanced node.
    • In the Max Degree of Parallelism box, select the maximum number of processors to use in parallel plan execution.
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