SNHA11: Troubleshoot continuous connection failures to SQL Server

Let us now learn how to troubleshoot connection failures to listener and SQL Server. In this video, we'll walk you through the steps to diagnose and resolve connection issues effectively. Agenda: 0:00 - Internals of connection to SQL Server: we'll look at a network diagram that includes the DNS Server, Application Server, SQL Server, and Domain Controller. This will help us understand the network setup and identify potential points of failure. 8:28 - Troubleshooting steps 11:17 - Issue one. We will troubleshoot connection failure with the below 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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 53) ========================================== 18:35 - Issue two: We will troubleshoot connection failure with the below 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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 2) ========================================== 25:25 - Issue three: We will troubleshoot connection failure with the below error: ========================================== Connection Timeout Expired. The timeout period elapsed while attempting to consume the pre-login handshake acknowledgement. This could be because the pre-login handshake failed or the server was unable to respond back in time. The duration spent while attempting to connect to this server was - [Pre-Login] initialization=3; handshake=996; (Microsoft SQL Server, Error: -2) ========================================== 29:24 - Issue four: We will troubleshoot connection failure with the below error: ========================================== A connection was successfully established with the server, but then an error occurred during the login process. (provider: SSL Provider, error: 0 - An existing connection was forcibly closed by the remote host.) (Microsoft SQL Server, Error: 10054) ========================================== NETSH command: ========================================== netsh trace start capture=yes traceFile=C:\MSLOG\trace.etl provider="Microsoft-Windows-Kernel-Process" keywords=0x70 level=0x4 maxSize=1024 report=no correlation=disable perfMerge=no ========================================== By following these steps, you can effectively troubleshoot and resolve continuous connection failures in SQL Server. Thank you for watching, and don't forget to like, comment, and subscribe for more tech support videos! 🧑‍💼►Follow me on LinkedIn - https://www.linkedin.com/in/bobirmirzo-arslanov-548960173 Full course sessions: 🚀►https://www.youtube.com/playlist?list=PLxuuX6jGq7knFZh8RmoZD6oDtWCHgWkap Watch all my playlists here: 🚀►Full course on Troubleshooting sessions: https://youtube.com/playlist?list=PLxuuX6jGq7kmlUblaWyfIh-iT5r0EWrJX&si=gC5FAhH9i6_b0waY 🚀►Full course on Encrypting connections to SQL Server- https://youtube.com/playlist?list=PLxuuX6jGq7kmqOCqYa1lFxQOKFgTfb8j8&si=bBwHhLsu6m5CjFft 🚀 ►SQL Server replication session: https://youtube.com/playlist?list=PLxuuX6jGq7km5E54qm0zc7REGXw6WD4C8&si=fQ_PVoGQ1S8SeI6X 🚀 ►SQL Server Always On Availability Group: https://youtube.com/playlist?list=PLxuuX6jGq7klnjr9OIGt8R1SN76pQzuEB&si=zZVr_sJnc7I9H8d3 🚀 ► SQL Server internals: https://youtube.com/playlist?list=PLxuuX6jGq7kk5_OkxbZ8QDZ2HFBDy2XZ2&si=U2rRfgS2y87t5SU4 🚀 ► Course in On-memory OLTP: https://youtube.com/playlist?list=PLxuuX6jGq7kmt6gfHUW5KhfXGaoSiDXOB&si=fVS1s2L6If36Zg-r