Create a Database Mirroring Endpoint for Windows Authentication (Transact-SQL)

Artikel
04/12/2023

Applies to: SQL Server

This topic describes how to create a database mirroring endpoint that uses Windows Authentication in SQL Server by using Transact-SQL. To support database mirroring or Always On availability groups each instance of SQL Server requires a database mirroring endpoint. A server instance can have only one database mirroring endpoint, which has a single port. A database mirroring endpoint can use any port that is available on the local system when the endpoint is created. All database mirroring sessions on a server instance listen on that port, and all incoming connections for database mirroring use that port.

Important

If a database mirroring endpoint exists and is already in use, we recommend that you use that endpoint. Dropping an in-use endpoint disrupts existing sessions.

In This Topic

Before you begin: Security
To create a database mirroring endpoint, using: Transact-SQL

Before You Begin

Security

The authentication and encryption methods of the server instance are established by the system administrator.

Warning

The RC4 algorithm is deprecated. This feature will be removed in a future version of SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature. We recommend that you use AES.

Permissions

Requires CREATE ENDPOINT permission, or membership in the sysadmin fixed server role. For more information, see GRANT Endpoint Permissions (Transact-SQL).

Using Transact-SQL

To Create a Database Mirroring Endpoint That Uses Windows Authentication

Connect to the instance of SQL Server on which you want to create a database mirroring endpoint.
From the Standard bar, click New Query.
Determine if a database mirroring endpoint already exists by using the following statement:
```
SELECT name, role_desc, state_desc FROM sys.database_mirroring_endpoints;   
```
Important

If a database mirroring endpoint already exists for the server instance, use that endpoint for any other sessions you establish on the server instance.

To use Transact-SQL to create an endpoint to use with Windows Authentication, use a CREATE ENDPOINT statement. The statement takes the following general form:

CREATE ENDPOINT *\<endpointName>*  

STATE=STARTED  

AS TCP ( LISTENER_PORT = *\<listenerPortList>* )  

FOR DATABASE_MIRRORING  

(  

[ AUTHENTICATION = **WINDOWS** [ *\<authorizationMethod>* ]  

]  

[ [**,**] ENCRYPTION = **REQUIRED**  

[ ALGORITHM { *\<algorithm>* } ]  

]  

[**,**] ROLE = *\<role>*  

)

Where:

<endpointName> is a unique name for the database mirroring endpoint of the server instance.
STARTED specifies that the endpoint is to be started and to begin listening for connections. A database mirroring endpoint typically is created in the STARTED state. Alternatively, you can start a session in a STOPPED state (the default) or DISABLED state.
<listenerPortList> is a single port number (nnnn) on which you want the server to listen for database mirroring messages. Only TCP is allowed; specifying any other protocol causes an error.

A port number can be used only once per computer system. A database mirroring endpoint can use any port that is available on the local system when the endpoint is created. To identify the ports currently being used by TCP endpoints on the system, use the following Transact-SQL statement:
```
SELECT name, port FROM sys.tcp_endpoints;  
```
Important

Each server instance requires one and only one unique listener port.
For Windows Authentication, the AUTHENTICATION option is optional, unless you want the endpoint to use only NTLM or Kerberos to authenticate connections. <authorizationMethod> specifies the method used to authenticate connections as one of the following: NTLM, KERBEROS, or NEGOTIATE. The default, NEGOTIATE, causes the endpoint to use the Windows negotiation protocol to choose either NTLM or Kerberos. Negotiation enables connections with or without authentication, depending on the authentication level of the opposite endpoint.

Note

To use Kerberos authentication for the communication between availability group (AG) endpoints, register a Service Principal Name for Kerberos Connections for the database mirroring endpoints used by the AG.

ENCRYPTION is set to REQUIRED by default. This means that all connections to this endpoint must use encryption. However, you can disable encryption or make it optional on an endpoint. The alternatives are as follows:

Value	Definition
DISABLED	Specifies that data sent over a connection is not encrypted.
SUPPORTED	Specifies that the data is encrypted only if the opposite endpoint specifies either SUPPORTED or REQUIRED.
REQUIRED	Specifies that data sent over a connection must be encrypted.

If an endpoint requires encryption, the other endpoint must have ENCRYPTION set to either SUPPORTED or REQUIRED.

<algorithm> provides the option of specifying the encryption standards for the endpoint. The value of <algorithm> can be one following algorithms or combinations of algorithms: RC4, AES, AES RC4, or RC4 AES.

The AES algorithm for the database mirroring endpoint uses a 128 bit key length.

AES RC4 specifies that this endpoint will negotiate for the encryption algorithm, giving preference to the AES algorithm. RC4 AES specifies that this endpoint will negotiate for the encryption algorithm, giving preference to the RC4 algorithm. If both endpoints specify both algorithms but in different orders, the endpoint accepting the connection wins. Provide the same algorithm explicitly to avoid connection errors between different servers.

Warning

The RC4 algorithm is deprecated. This feature will be removed in a future version of SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature. We recommend that you use AES.
<role> defines the role or roles that the server can perform. Specifying ROLE is required. However, the role of the endpoint is relevant only for database mirroring. For Always On availability groups, the role of the endpoint is ignored.

To allow a server instance to serve as one role for one database mirroring session and different role for another session, specify ROLE=ALL. To restrict a server instance to being either a partner or a witness, specify ROLE = PARTNER or ROLE = WITNESS, respectively.

Note

For more information about Database Mirroring options for different editions of SQL Server, see Features Supported by the Editions of SQL Server 2016.

For a complete description of the CREATE ENDPOINT syntax, see CREATE ENDPOINT (Transact-SQL).

Note

To change an existing endpoint, use ALTER ENDPOINT (Transact-SQL).

Example: Creating Endpoints to Support for Database Mirroring (Transact-SQL)

The following example creates database mirroring endpoints for the default server instances on three separate computer systems:

Role of server instance	Name of host computer
Partner (initially in the principal role)	`SQLHOST01\.`
Partner (initially in the mirror role)	`SQLHOST02\.`
Witness	`SQLHOST03\.`

In this example, all three endpoints use port number 7022, though any available port number would work. The AUTHENTICATION option is unnecessary, because the endpoints use the default type, Windows Authentication. The ENCRYPTION option is also unnecessary, because the endpoints are all intended to negotiate the authentication method for a connection, which is the default behavior for Windows Authentication. Also, all of the endpoints require the encryption, which is the default behavior.

Each server instance is limited to serving as either a partner or a witness, and the endpoint of each server expressly specifies which role (ROLE=PARTNER or ROLE=WITNESS).

Important

Each server instance can have only one endpoint. Therefore, if you want a server instance to be a partner in some sessions and the witness in others, specify ROLE=ALL.

--Endpoint for initial principal server instance, which  
--is the only server instance running on SQLHOST01.  
CREATE ENDPOINT endpoint_mirroring  
    STATE = STARTED  
    AS TCP ( LISTENER_PORT = 7022 )  
    FOR DATABASE_MIRRORING (ROLE=PARTNER);  
GO  
--Endpoint for initial mirror server instance, which  
--is the only server instance running on SQLHOST02.  
CREATE ENDPOINT endpoint_mirroring  
    STATE = STARTED  
    AS TCP ( LISTENER_PORT = 7022 )  
    FOR DATABASE_MIRRORING (ROLE=PARTNER);  
GO  
--Endpoint for witness server instance, which  
--is the only server instance running on SQLHOST03.  
CREATE ENDPOINT endpoint_mirroring  
    STATE = STARTED  
    AS TCP ( LISTENER_PORT = 7022 )  
    FOR DATABASE_MIRRORING (ROLE=WITNESS);  
GO

Related Tasks

To Configure a Database Mirroring Endpoint

To View Information About the Database Mirroring Endpoint

sys.database_mirroring_endpoints (Transact-SQL)

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