The FrontBase server can be stared as FRontBase -FBExec=No -port= port number database name.
The client contacts FBExec to obtain the port number to use for the connection to the database. if the database name is a number the system will use that as a port number and it will not ask FBExec for the port number. The FrontBase server can be stared as FRontBase -FBExec=No -port= port number database name.