hope this helps/ucs-overview and /univention-management-console/ are served by Apache, changing "umc/http/port" will not solve your problem.
Instead of changing the port for the administration pages you might consider using Access Control in Apache.
The topic itself is currently in discussion. The more I think about it and the use cases for UCS, the more I would think that this is something which should be built in as a feature instead of just document a workaround.
In the meantime you can choose between
- changing the templates for the Apache -Config files
- placing a .htaccess into the directories you want to protect
The last one is obviously the quickest but may have drawbacks during upgrades or show side effects. It currently works for me.
Assuming your internal network is 192.168.1.0 you may try to create the file /var/www/univention-managment-console/.htaccess with the following content:
Allow from 127.0.0.0/255.0.0.0 ::1/128
Allow from 192.168.1
Deny from all
You can also copy the .htaccess to /var/www/ucs-overview.
Of course, having a general access control for the whole Apache-DocRoot and defining exclusions for ActiveSync and WebAccess would provide more security.