dotnet/Documentation/compatibility/sql-server-database-connection-that-resolves-to-localhost.md

Attempting a TCP/IP connection to a SQL Server database that resolves to localhost fails

Scope

Minor

Version Introduced

4.6

Version Reverted

4.6.2

Source Analyzer Status

NotPlanned

Change Description

In the .NET Framework 4.6 and 4.6.1, attempting a TCP/IP connection to a SQL Server database that resolves to localhost fails with the error, "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: 26 - Error Locating Server/Instance Specified)"

• Quirked // Uses some mechanism to turn the feature on or off, usually using runtime targeting, AppContext or config files. Needs to be turned on automatically for some situations.
• Build-time break // Causes a break if attempted to recompile

Recommended Action

This issue has been addressed and the previous behavior restored in the .NET Framework 4.6.2. To connect to a SQL Server databsae that resolves to localhost, upgrade to the .NET Framework 4.6.2.

Affected APIs

• Not detectable via API analysis

Category

Data