time control for remote ssh/sftp access

[RalfGesellensetter <rgx@gmx.de>]

Dear list,

one of tjener's (and therefor Skolelinux's) strengths is:
everything is already at your service, like sftp:

If you tell your teachers that they could easily upload
their work from their bureau at home, 
they might cheer and cry for more.

But, of course, you won't allow this during lessons, 
otherwise web browsing might collapse.

What solutions do you take? cron jobs to rotate sshd.conf?
iptables (?) for bandwith throttling? Any hints on how to
limit logins to given times or hosts?

Thanks
Regards
Ralf