Can't connect to remote SQL server from some machines Our web server uses SQL Server 2008 R2. I have one development machine that connects to it with the IP address through SSMS and when testing my aspx website. I have several other machines though that can't connect to the IP through SSMS. I'm getting this 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 the instance name is correct and the SQL Server is configured to allow remote connection.
  (provider: Named Pipes provider:40-could not open a connection to SQL Server)
  (Microsoft SQL Server, Error:53)


I've got TCP/IP enabled, port 1433 open, all of that. Remember that I can connect from one development machine, but not others.
Here are some of the things from my connection issue checklist


Check for an alias on the machine that can't connect
Check for firewall rules
Check and make sure the SQL Server drivers on the machines that don't work are up to date.
Try connecting with servername:port rather than just servername
Try pinging the SQL Server IP address from the machines that can't connect.