> 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.