How To Check If SQL Server Is Not Able To Connect Due To Firewall In Windows 2012

If you are handling issues beyond your scope ,its tough being a DBA. But DBA is just not responsible to fix issue, he also have to proof if issue doesn't belong to him.

Today i got Firewall issue in one of my Windows 2012 server where team have installed 2 instances of sql server 2012 and 3 SQL server 2008 instances.

  • All instances have TCP\ IP protocol  and shared memory enabled 
  • Few instances were using dynamic ports and few  were using static port
  • All instances have there separate service accounts

During initial testing DBA have test all server locally and they were connecting fine.
                     After hand over servers to application they complain that they are not able to connect sql server instances.

Being a DBA we also try to connect from other servers but no luck, As servers are in sub domain we were doubting there could be domain issues but we were able to ping servers successfully but not to sql instances.

So we doubted firewall setting might be issue, But just raising to network team can go against us so we have to prove that this issue doesn't belong to us. So we did below steps to check if there is any firewall settings.

Steps to check Firewall issue:

1. Connect to other server ,Go to Start menu, click Run.

2. In the Open box, type mmc -a to open the Microsoft Management Console in author mode.

3. On the File menu, click Add/Remove Snap-in.

4. In the Add/Remove Snap-in window, click Add.

5. In the Add Standalone Snap-in window, click Computer Management and then click Add.

6. In the Computer Management window, click Another computer, type the name of the remote computer you wish to manage, and then click Finish.

7. If there is firewall issue you will get below window with error.

8. Send this mail to your network team and you are good and don't expect any escalation.

9. If you are admin on server than you can also change firewall setting using below link 

Firewall Setting (Enable / Disable):

Write comments
  1. I prefer the PING command before trying this, but if the ping is disabled in target server, I think this method can be used (not sure)

    1. Hi Biju

      Ping is very good utility and not affected by firewall in most of the scenarios. So ping will work in almost all conditions but when sql or application try to connect than only firewall will come in picture


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