Original von probono
You're right, multiuser is not a issue here since I am talking about a home machine that runs always under the same user only.
I'll try it again.
The system architecture is inherently multi user.
I am the only human user on this system, but processes belonging to 4 users are currently running. Several as "root", two as "daemon" and apache is runnings as "www-data"
So is there any chance to find out (e. g.with a shell script or otherwise) whether any application wants to create traffic?
I think you can't do that on the application level.
You can just monitor the network device and see if traffic wants to go through.
Autodialers lke wvdial do this to see when they have to dial in.
Maybe the autodialer you use has the possibility to execute a script before dialing.
In this case you could have a script determine one user having a X11 display and, in case this user has authenticated localhostwith xhost, popup a dialog asking for dial-in permission.
erugger66 hinted that SuSE has a tool doing this all by itself.
Perhaps it is available as a single package as well.
Cheers,
_