I’m struggling with the postfix configuration and spam and virus checking. I don’t know where to place the spam and virus checking. Are there example files for
which integrate nicely with virtualmin (users can choose if they want spam and virus checking).
It depends on what you want to do. Have a look at the Servers>Spamassassin Webmin module. It has a function to set up procmail so Spamassassin will be user-configurable via Usermin.
ClamAV doesn’t have per-user options in Webmin/Usermin, that I know of. You can control it globally with a third-party module:
That seems to work best when doing ClamAV with amavisd-new.