> Are all clients connecting using the same protocol? And the same > adress resolution? >
Some clients connect using TCP/IP but the gbak is local. Also the owner sometimes connects with isql for special queries. > Can, at the same time you are being denied the permissions, other > users (re-)connect and work without problems (== is this only a > problem when you are trying to access via SYSDBA or OWNER? > It is only a problem trying to connect locally as the database owner. As root there is no problem connecting with isql or doing a backup with gbak. Even when local connections do not work the remote connections work. As I said before. After the machine boots up there is no problem connecting locally but after a several days suddenly connecting local stops working and no changes to the database permissions occurred.
