When Exchange 2003 SP2 is released the SPAM filter known as Intelligent Message Filter or IMF will be included in the SP. Also it will be renamed so it matches the name that Outlook 2003 uses.

Another filter that is added in the SP is Sender ID. A myth on Sender ID is, that if you enable it that you won't receive any email from domains that son't have a Sender ID in there DNS record in there DNS zone. This is not the case! Sender ID filter will check if a Sender ID DNS record is present, then it will check if the email that is received somes from the registerd SMTP server, if this is not the case only then an action will be taken. What action is your choice, reject, delete, nothing. So when there is no Sender ID of the Domain registerd the Sender ID filter ignores it and the email will get through anyway.

Yet another filter is added, the anti phising filter, this filter wont be configurable and therefor won't show up in the UI, just as anti-spam and its SCL-flag (SPAM Confidence Level) now a PCL (Phishing Confidence Level) flag is set to anincoming email, both flags gives Exchange a more granular choice of what to do with the message.