Authentication are only necessary when using personal accounts outside the domains of Tornevall Networks.
The authentication is always the credentials you are using to read and write mail via tornevall.net
Current Solution Visualized
We use spamassassin running agains some RBL's. This includes both spamcop, uribl, dnsbl.tornevall.org and fraudbl.org, as a few examples. Antivirus amongst others is clamd and NOD32.