Firewall configuration for SQL 2008/2005 Named Instance

1. Open TCP and UDP port 1434. UDP port 1434 is used by SQL Browser to handle instance name resolution for SQL Server. TCP Port 1434 is used for SQL server dedicated Admin connections.

2. If SQL Server has been configured for dynamic port (Default configuration) then add SQL server service to firewall exception list. Find the path name of sqlserver.exe, usually it will be below (Standard install)-

C:\Program Files\Microsoft SQL Server\MSSQL10.{Instance Name}\MSSQL\Binn\sqlservr.exe

Add above to the firewall exception list. This will enable SQL server to communicate with clients on any port it’s running on through SQL Browser.

If SQL Server is configured to listen on a fixed port, then instead of adding sqlservr.exe to the exception list, you can open the Inbound communication for the TCP port.