How to deny access to /univention portal from internet

Hey,

that’s just basic Apache access control: allow access from your local network’s IP addresses, deny access from everywhere else. Try putting something like this in e.g. /etc/apache2/conf-available/umc-access.conf, then run a2enconf umc-access and reload Apache:

<Location /univention/>
  Require ip 192.168.0.0/24 # put your local network address range here
  Require all denied
</Location>

Untested.

Kind regards,
mosu