How to handle SQL Network Interfaces error 28

When attempting to connect to a SQL Server instance using SQL Server Management Studio or another method, the error "SQL Network Interfaces error 28" frequently occurs.

As part of our server management services for web hosts and online service providers, we at Skynats have encountered a number of these SQL-related problems.

Today, we'll examine this error's root cause and possible solutions.

What results in the error "SQL Network Interfaces error 28"

Let's first talk about the reasons why this error occurs before moving on to the solution. Here are some of the various causes of this error.

• The instance name for SQL Server is not valid.

• Blocking of your SQL Server instance's remote access

• Both SQLBROWSER.EXE and SQLSERVR.EXE use blocked ports. The server's firewall consequently rejects connections.

• There is no running SQL Server Browser service (sqlbrowser).

For instance, the error looks like this.

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 28 – Server doesn’t support requested protocol)

Fixing SQL Network Interfaces error 28

These are the recommendations our support engineers make to our clients to fix this issue.

Verify that the client machine can connect to the server that houses the SQL server. To check the connectivity for that, you can use ping and telnet.

Make sure your server's SQL server is functioning properly. Make sure to look at SQL Server services for that.

The firewall ports 1433 and 1434 for SQL Server and SQL Server Browser, respectively, must be left open.

Make sure the name of the SQL Server instance is accurate. Additionally, make sure the connection string's reference to the SQL Server instance is written correctly.

Make sure to enter the full SQL Server instance name if your instance has a name like SERVERNAMESQL2017.

Ensure that the server's SQL Server Browser service is running.

For your SQL Server instance, enable remote connections. Using the SQL Server Configuration Manager tool, you can instruct SQL Server to accept connections from remote hosts using the TCP or named pipes protocols. The steps to enable remote connections are listed below.

• Open SQL Server Configuration Manager first. Expand SQL Server Network Configuration in the left side pane, and then click Protocols for InstanceName. It will say "Protocols for MSSQLSERVER" if your server has a default instance.

• All three protocols should now be visible in the right-side panel. They are TCP/IP, Named Pipes, and Shared Memory.

• Enable TCP/IP and named pipes. To do so, perform right-click on the protocol name and select Enable. The protocol icon will now change to indicate that it is enabled.

• Finally, to activate the changes, restart the SQL Server services.