We have two instances of SQL installed on one Server 2012 box, and need to run queries from one to the other. At the moment we are getting the error
OLE DB provider "SQLNCLI11" for linked server "servername\instance" returned message "Login timeout expired".
OLE DB provider "SQLNCLI11" for linked server "servername\instance" returned message "A network-related or instance-specific error has occurred while establishing a connection to SQL Server. Server is not found or not accessible. Check if instance name is correct and if SQL Server is configured to allow remote connections. For more information see SQL Server Books Online.".
Msg -1, Level 16, State 1, Line 0
SQL Server Network Interfaces: Error Locating Server/Instance Specified [xFFFFFFFF].
Try opening your SQL Server Config Manager and under the SQL Network Config --> Instance in question --> Open Properties on the TCP/IP and check the IP Address Tab, and scroll down. Most times it dynamically creates a port. If you are changing this to a static Port, you need to remove the Dynamic info and put your port in the TCP PORT field only. This should only be needed though if the program you are using does not work with Dynamic ports for some reason (Some legacy apps do). I would make sure that Dynamic port is opened on the Windows Firewall. Usually I just add that port to the pre-created SQL Server Firewall Rule under the Windows Firewall Advanced settings.
Thanks for your comment dmanning unfortunately I can't see that this is the problem, I have checked the settings which look into and the firewall is off, thanks for taking the time to point this out to me though