Difference between TCP and UDP network protocols

Question: What is the difference between TCP and UDP? When is TCP used instead of UDP? Answer: SQL Server databases are shared across different locations , so it’s important to understand network communications . To read on the importance network tuning and monitoring read SQL Server – netstat monitoring and tuning performance (SQL ... The main difference between UDP (User Datagram Protocol ) and TCP (Transmission Control Protocol) is in the handling of the data packets when sent. TCP is all about guaranteeing the recipient receives the packets in order . When the recipient receives a packet, a message is... Read more →

How to list Domain Controllers in a Domain with nltest

Question:How can I list the Domain Controllers for a domain? There have been some Domain Controller issues and trusted authority login failures - and I'm using Troubleshooting Error: 18452, Severity: 14, State: 1 (SQL Server DBA). The Domain Controller team would like to see a list of Domain Controllers available from a server.I’m using Windows 2008 R2 Enterprise Server Answer: The nltest command line tool is useful for Domain Controller information. It arrives as part of Windows 2008 . The tool allows the operator to complete a number of tests such as trust status and domain controller replication status. Nltest... Read more →

SQL Server Configuration Manager from Command Line

Question: How can I start SQL Server Configuration Manager from Command Line? Answer: To start SQL Server Configuration Manager from Command line is a slightly different reference for every SQL Server Version. You can access information normally obtained therough SQL Server Configuration Manager in alternative ways such as SQL Server – Find SQL Server tcp port with Powershell . But SQL Server Configuration Manager remains my primary method to manager configurations For 2005 - SQLServerManager.msc For 2008/R2 - SQLServerManager10.msc For 2012 - SQLServerManager11.msc For 2014 - SQLServerManager12.msc For 2016 - SQLServerManager13.msc For 2017 - SQLServerManager14.msc Read more on command line... Read more →

Using the tcp: prefix for SQL Server connections : Force use of TCP protocol

Question: I’ve been advised to use the prefix tcp: for a SQL Server connection, during some connection troubleshooting. Could you explain the purpose of using the tcp: prefix , such as : Tcp:MYSERVER\INSTANCE1 Answer: The tcp: prefix will force the usage of TCP/IP transport. There are certain situations , where using the tcp: will allow a valid SQL Server connection. When using the tcp: prefix you’re requesting to explicitly connect through TCP/IP. If the server is not listening on TCP/IP , your options are either to not use the tcp: prefix or locate and enable the tcp protocol. Use the... Read more →

Troubleshooting Error: 18452, Severity: 14, State: 1

Error: 18452, Severity: 14, State: 1 is a notoriously difficult SQL Server error code to troubleshoot. If associated with Error: 17806, Severity: 20, State: 2 , another layer of complication is added. A typical combination of these error codes would appear in the SQL Server Error Log , such as : Login failed for user ''. The user is not associated with a trusted SQL Server connection. [CLIENT: xxxxxxx] Error: 17806, Severity: 20, State: 2. SSPI handshake failed with error code 0x80090311 while establishing a connection with integrated security; the connection has been closed. [CLIENT:xxxxxx] Error: 18452, Severity: 14, State:... Read more →