question

alisha.asa avatar image
alisha.asa asked

Network related error or sql instance error .

we have built two new application servers A and B. while user is trying to access the database server C from A and B he is facing 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 SQL Server is configured to allow remote connections" There are other application servers connected to C and working fine. Only probelm with New servers A and B.
networksqlerror
3 comments
10 |1200
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.

KenJ avatar image KenJ commented ·
can you ping the sql server from the new application servers? can you telnet into the sql server port from the new servers? do the new servers use the same connection string as server C? are you connecting using server name or IP address?
0 Likes 0 ·
Grant Fritchey avatar image Grant Fritchey ♦♦ commented ·
For all answers that are helpful, you should click on the thumbs up. If any one answer lead to a solution, you should click on the check mark next to that answer.
0 Likes 0 ·
Grant Fritchey avatar image Grant Fritchey ♦♦ commented ·
Don't forget to vote on the answers you've received and mark one as a solution.
0 Likes 0 ·

3 Answers

·
sqlaj 1 avatar image
sqlaj 1 answered
Have you confirmed the SQL engine is running? I just powered up a few test VMs and one of them I could not connect to SQL. I discovered the SQL Engine and Agent had not started.
10 |1200
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.

Blackhawk-17 avatar image
Blackhawk-17 answered
Is SQL Server set to use a non-default port and is the SQL Browser service running?
10 |1200
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.

pipthegeek avatar image
pipthegeek answered
Can you ping the SQL server? Does nslookup resolve the host name of the SQL server? Is SQL server running on the default port or is it a named instance? The rest of my suggestions are only relevent if it NOT running on the default port. The most likely problem now is that something is preventing the client from determining the port of the SQL instance. This is done using the SQL browser service, so as others have suggested, check the browser service is running on the SQL server. As others can connect I expect it is running. My next suggestion is to turn off the windows firewall on one of the application servers. I have had problems where the windows firewall prevents the reply from the SQL Browser. If the connection now works then you can either leave it turned off or add an appropriate rule to allow the SQL Browser traffic. SQL Browser operates on UPD port 1434, so either allow that port or you can add an allow rule for the application that needs to connect to SQL. It is also possible that the firewall on the SQL server is blocking the browser service, but I think that is unlikely in your case becuase you said you are only having issues with two new application servers.
10 |1200
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.

Write an Answer

Hint: Notify or tag a user in this post by typing @username.

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.