Exchangepedia | Install anti-spam agents on Hub Transport server
Exchange Server 2007 SPAM filtering features without using Exchange Server 2007 Edge Server
How to change spam settings on Exchange 2007 / SBS 2008 to enable some / all / more spam to be delivered to an account for analysis - David Overton's Blog - DavidOverton.com
How to Configure a Barracuda Spam Filter Firewall to Relay Mail to Exchange Server | DALARIS TECH BLOG
Office 365 Spam Filter: A Complete Setup Guide
No Spam Today: Anti Spam Filter for Exchange or any other Mail Server