We checked the clients and all are using tcp/ip.

The problem is now tracked down and it appears to be the Delphi DBExpress framework on the client side. There is a...

The clients *should* be using TCP/IP, but we didn't check that so far. Will check this now for all clients. To be continued...

No ODBC connections. The client is a Delphi application and uses the DBExpress framework for the database connection. In the test app there is a connection component and a query...