Spamfilter
 

I'm trying to figure out how spamfilter works.
Actually I have to create a spamfilter user to use white/blacklist.

But there is not check againt this user as I can see, so, user1@domain1.tld can create a user called user2@domain2.tld

Is this ok ? Is not possible to use whitelist and blacklist with no need to create spamfilter user?

Is possibile to set postfix whitelist/blacklist privileges to certain users?
For example, VPS administrator should be able to filter at postfix level, hosting users should not.

The spamfilter functions are described in detail in the amvis manual.ISPConfig uses the default amavis sql setup:

http://www.ijs.si/software/amavisd/