Firstly I would like to make a disclaimer: Webmin use at your own peril.
Zentyal dev team there are some really good features in webmin that could provide much for admins.
The file manager & cron pages are excellent also many others like the disk management and I also like having database management all in one place.
I don't really like quoting webmin as Zentyal is sort of a replacement but it does have a few utilities that make it a good companion.
Its always good to search the forum first for any knowledge and if you did you would see an excellent thread on how to get webmin.
http://forum.zentyal.org/index.php/topic,9389.msg39044.html#msg39044Follow the instructions there and remember to create a webmin service port 10000 and add that service to the firewall allow rules depending on your location to the server.
So from there
https://myserverip:10000 and we should be able to logon as root with the admin password.
In the other section of webmin and choose the file-manager
However you set up the filtering on Zentyal is saved in /etc/dansguardian/dansguardianf1.conf
So I am going to set up a transparent proxy with my filtering set and save changes
Then in webmin I am going to copy dansguardianf1.conf and paste it as dansguardianf1.conf.filter
Then I am going to set up a transparent proxy that allows access without filtering and save changes
Then in webmin I am going to copy dansguardianf1.conf and paste it as dansguardianf1.conf.nofilter
Then webmin system scheduled cron jobs I am going to create a new cron job and run as root
cd /etc/dansguardian && cp dansguardianf1.conf.filter dansguardianf1.conf && /etc/init.d/zentyal squid restart
Set a time to filter and give it a description.
Then another cron job.
cd /etc/dansguardian && cp dansguardianf1.conf.nofilter dansguardianf1.conf && /etc/init.d/zentyal squid restart
Set a time to stop filtering and give it a description.
I think thats it but if the community would like to provide better methods then please do.
I haven't actually checked but I presume dansguardianf1.conf the filter list settings is all I need to change. Otherwise its the same procedure but do the same with /etc/dansguardian/dansguardian.conf
Stuart