Wednesday, July 20, 2016

Handout to Resolve SQL Server Connectivity Issues [Guest Post]

This post is written by Andrew Jackson.

Problem Statement
While launching Microsoft SQL Server Management Studio, sometimes user faces a problem when they try to connect with the server. After clicking on Connect button, an error message box appears, which indicates that there is some connectivity issues in the server.

End user becomes tensed when they find it impossible to connect with the server and such errors are known as SQL server connectivity issues. In this blog, we are going to discuss that why does these connectivity issues occurs and what are the measures to troubleshoot them.

Causes of Connectivity Issues in SQL Server
Generally, when one fails to connect to the SQL server, the reasons may be:
  • The network of SQL server may be disconnected or slow
  • The SQL server of machine may be improperly configured
  • There must be some problem with firewall or other network devices
  • The connection between two servers may be disconnected
  • Applications related to the server may be improperly configured
  • There may be authentication error or log-in issue on the server

Approaches To Resolve The Problem
In this section, we are going to discuss different techniques to resolve SQL server connectivity issues. Follow the below-mentioned procedure for resolving your problem:
NOTE: After performing each step, restart your machine and then try to connect to the server. If you are successfully connected to the server, then stop your procedure there only; else go to next step.

STEP 1: Resolving Networking Issue
As discussed earlier that network connection could be the one reason for connectivity error because a stable network is being required for establishing a remote connection. Therefore, the first approach should be to examine the network by executing the following commands (given in the snapshot):

STEP 2: Modify the SQL Server Configuration
Use SQL Server Configuration Manager for examining the protocols, which are used for running targeted SQL server. The server supports TCP protocol, Shared memory, and Named Pipes. If the protocols are disabled, then enable them by making use of Configuration manager. After performing configuration, restart your SQL server machine.

STEP 3: Improving Network Devices Functioning
Network devices like firewall, routers, gateway, etc., may be settled in such a way that they block the connection request. The rules of firewall may be configured in such a way that it blocks the request of SQL connection. Therefore, for resolving such error you will have to disable the functioning of firewall because if the firewall is disabled, then its will stop its functioning & hence, you will be able to connect with SQL server. Moreover, after having a successful connection, you can again enable the functioning of the firewall.

STEP 4: Resolving the Client Driver Issue
This solution is applied on the client machine. Go through the following description to troubleshoot the SQL Server connectivity issues:

“Execute the below-shown command to log-in into another client computer via TCP protocol. If TCP is disabled, then enable it and then use SQL Management Studio, OSQL, and SQLCMD for testing SQL connections.”

STEP 5: Properly Configure SQL Related Applications
Once again reconfigure the applications related to SQL server and then go through the following assumptions:
  1. The application is running on your account or on a different account. If the application is running on the different account, then configure it within your account.
  2. Analyze your connection string and check whether the string is compatible with your driver or not. If not, then make it compatible with your driver.

STEP 6: Resolve Authentication & Log-in Faults
The last step or you can say the end approach to resolve the connectivity problem is to troubleshoot faults, which occurs at the time of authentication procedure and during log-in. It relates to a network connection, machine’s operating system, and the server database.
  1. Make sure that the input credentials are valid
  2. If you are using SQL auth, then mixed authentication should be enabled
  3. Examine all the eventlog of your machine and collect some more information
  4. Analyze the permissions whether they are enabled for logging into the account or not. If not, then instantly enable them.
After having a brief discussion about how to deal with SQL Server connectivity issues, one can wind up with the fact that these connectivity issues are due to fault in the network, network devices, or improper configuration. Therefore, one can troubleshoot the SQL connection error 40 and SQL error 26 by going through the mentioned steps.

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