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Aliases (SQL Server Configuration Manager)

  • Стаття

Applies to: SQL Server - Windows only

An alias is an alternate name that can be used to make a connection. The alias encapsulates the required elements of a connection string, and exposes them with a name chosen by the user. To create an alias for the Microsoft SQL Server clients on this computer, right-click Aliases in the console pane, and then select New Alias. To configure an existing alias for the SQL Server clients on this computer, select Aliases in the console pane, right-click the desired existing alias in the details pane, and then select Properties.

Примітка

Aliases for SQL Server are a client side configuration. Each client computer that uses the alias must have an identical alias configuration, and SQL Server Configuration Manager is not the only tool that can be used to create or manage aliases.

SQL Server 2022 and later versions do not support creating aliases using SQL Server Configuration Manager. To create an alias for SQL Server 2022 and later versions, use the SQL Server Client Network Utility tool.

When to use an alias

By default, SQL Server connects to a local instance of SQL Server using the Shared Memory protocol, and to an instance of SQL Server on another computer using either TCP/IP or Named Pipes. Create an alias when you're using TCP/IP or named pipes, and you want to provide a customized connection string, or when you want to use a name other than the server name for the connection.

Examples

  • SQL Server isn't listening on the default TCP/IP port of 1433 so you want to provide a connection string with a different port number.

  • SQL Server isn't listening on the default named pipe so you want to provide a connection string with a different pipe name.

  • An application expects to connect to a database on the server named ACCT, but that database has been consolidated as an instance named ACCT on a server named CENTRAL. The application can't easily be changed. Create an alias named ACCT, with a connection string pointing to CENTRAL\ACCT.

Alias properties

Alias Name

The name (alias) that you want to use to refer to this connection.

Pipe Name or Port Number

Additional elements of the connection string. The name of this box varies with the selected protocol.

Protocol

The protocol used for the connection.

Server

The name of the Microsoft SQL Server instance being connected to.

Shared memory connections

Connections to SQL Server from a client running on the same computer use the shared memory and named pipes protocols. Shared memory has no configurable properties. Shared memory is always tried first, and can't be moved from the top position of the Enabled Protocols list in the Client Protocols Properties list. The Shared Memory protocol can be disabled, which is useful when troubleshooting one of the other protocols.

You can't create an alias using the shared memory protocol, but if shared memory is enabled, then connecting to the Database Engine by name, creates a shared memory connection. A shared memory connection string uses the format lpc:<servername>[\instancename].

Connect to the local server using shared memory

When connecting to SQL Server running on the same computer as the client, you can use (local) as the server name. This value isn't encouraged as it leads to ambiguity, however it can be useful when the client is known to be running on the intended computer. For instance, when creating an application for mobile disconnected users, where SQL Server runs on laptop computers and stores project data, a client connecting to (local) would always connect to the SQL Server running on the laptop. The word localhost or a period (.) can be used in place of (local).

Examples of shared memory connections

The following names connect to the local computer with the shared memory protocol if it's enabled:

  • <servername>
  • <servername>\<instancename>
  • (local)
  • localhost

You can't create an alias for a shared memory connection.

Примітка

Depending on the configuration of the server, specifying an IP address in the Server box will result in a named pipes or TCP/IP connection.

TCP/IP connections

To connect to the SQL Server using an alias with TCP/IP, you must:

  • Specify an Alias Name.

  • For the Server, enter either a server name to which you can connect using the ping utility, or an IP address to which you can connect using the ping utility. For a named instance, append the instance name.

  • Specify TCP/IP for the Protocol.

  • Optionally, enter a port number for the Port No. The default is 1433, which is the port number of the default instance of the Database Engine on a server. To connect to a named instance or a default instance that isn't listening on port 1433, you must provide the port number, or start the SQL Server Browser service. For information on configuring the SQL Server Browser service, see SQL Server Browser Service.

At the time of connection, the SQL Server Native Client component reads the server, protocol, and port values from the registry for the specified alias name, and creates a connection string in the format tcp:<servername>[\<instancename>],<port> or tcp:<IPAddress>[\<instancename>],<port>.

Примітка

The Windows Firewall closes port 1433 by default. Because SQL Server communicates over port 1433, you must reopen the port if SQL Server is configured to listen for incoming client connections using TCP/IP. For information on configuring a firewall, see "How to: Configure a Firewall for SQL Server Access" in SQL Server Books Online or review your firewall documentation.

SQL Server and SQL Server Native Client fully support both Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6). SQL Server Configuration Manager accepts both IPv4 and IPv6 formats for IP addresses.

Examples of TCP/IP alias settings

Connecting by server name

Alias Name: <serveralias>
Port No: <blank>
Protocol: TCP/IP
Server: <servername>

Connecting by server name to a named instance

Alias Name: <serveralias>
Port No: <blank>
Protocol: TCP/IP
Server: <servername>\<instancename>

Connecting by server name to a specified port

Alias Name: <serveralias>
Port No: <port number>
Protocol: TCP/IP
Server: <servername>

Connecting by IP address

Alias Name: <serveralias>
Port No: <blank>
Protocol: TCP/IP
Server: <IPAddress>

Примітка

For information on specifying the network protocol as a sqlcmd parameter, see sqlcmd - Connect to the database engine.

Named Pipes connections

Unless changed by the user, when the default instance of Microsoft SQL Server listens on the named pipes protocol, it uses \\.\pipe\sql\query as the pipe name. The period indicates that the computer is the local computer. The pipe indicates that the connection is a named pipe, and sql\query is the name of the pipe. To connect to the default pipe, the alias must have \\<computer_name>\pipe\sql\query as the pipe name. If SQL Server has been configured to listen on a different pipe, the pipe name must use that pipe. For instance, if SQL Server is using \\.\pipe\unit\app as the pipe, the alias must use \\<computer_name>\pipe\unit\app as the pipe name.

To connect to the SQL Server using an alias with named pipes, you must:

  • Specify an Alias Name.

  • Select Named Pipes as the Protocol

  • Enter the Pipe Name. Alternatively, you can leave Pipe Name blank and SQL Server Configuration Manager will complete the appropriate pipe name after you specify the Protocol and Server.

  • Specify a Server. For a named instance you can provide a server name and instance name.

At the time of connection, the SQL Server Native Client component reads the server, protocol, and pipe name values from the registry for the specified alias name, and creates a pipe name in the format np:\\<computer_name>\pipe\<pipename> or np:\\<IPAddress>\pipe\<pipename>. For a named instance, the default pipe name is \\<computer_name>\pipe\MSSQL$<instance_name>\sql\query.

Примітка

The Microsoft Windows Firewall closes port 445 by default. Because Microsoft SQL Server communicates over port 445, you must reopen the port if SQL Server is configured to listen for incoming client connections using named pipes.

Examples of Named Pipes alias settings

Connecting by server name to the default pipe

Alias Name: <serveralias>
Pipe Name: <blank>
Protocol: Named Pipes
Server: <servername>

Connecting by IP Address to the default pipe

Alias Name: <serveralias>
Pipe Name: <blank>
Protocol: Named Pipes
Server: <IPAddress>

Connecting by server name to a nondefault pipe

Alias Name: <serveralias>
Pipe Name: \\<servername>\pipe\unit\app
Protocol: Named Pipes
Server: <servername>

Connecting by server name to a named instance

Alias Name: <serveralias>
Pipe Name: \\<servername>\pipe\MSSQL$<instancename>\SQL\query
Protocol: Named Pipes
Server: <servername>

Verify your connection protocol

The following query returns the protocol used for the current connection.

SQL 
SELECT net_transport
FROM sys.dm_exec_connections
WHERE session_id = @@SPID;

Related content

Network Protocols and Network Libraries