Table 1: Spam- and Content-Filtering features in Different Exchange Versions

Exchange 5.5

Exchange 2000 Server

Exchange Server 2003

Exchange Server 2007

No built-in features

Sender filtering

Exchange 2000
features plus
connection filtering with RBL support, recipient filtering, authenticated Distribution Groups, content filtering with SCL support (from SP1 onward), SenderID support (from SP2 onward)

Exchange 2003
features plus
special message hygiene server role (Edge Transport server), safelist aggregation, Edge Transport rules, automatic spam signature updates, sender reputation and protocol analysis, attachment filtering, content filtering with quarantine capability