Spamassassin configuration and blacklist/whitelist

Hello,

I installed Virtualmin under Debian 7 and created 3 virtual servers. I’ll use it as a mail server.

The first thing I’d like to do is create a whitelist of domains and senders for all virtual servers, as well as a blacklist of known spammers (which are local spammers and usually are not listed in RBLs).

After inspecting /etc/spamassassin/local.cf I noticed that every line within the file is commented out, so I’m gessing Virtualmin uses a custom location for Spamassassin’s configuration file.

If so, where is the configuration located?

if not, can I edit /etc/spamassassin/local.cf safely?

Thanks.