Other Exchange Hosted Services

Microsoft hosts mail security and archiving services for Exchange Online that can also enhance on-premises Exchange systems. The services include the following:

Exchange Online Protection is a Microsoft-hosted service that filters malware, spam, and other unwanted message content for Exchange Online. It can also be used in customer- and partner-hosted Exchange Server installations to filter messages before they reach the installation’s servers. It receives frequent improvements: In 2014, for example, it added DomainKeys Identified Mail (DKIM) validation of sender domains for connections over IPv6, and removal of messages with invalid recipients, using recipient information stored in Azure Active Directory. Likely improvements in 2015 include DKIM over IPv4 and refinements for distinguishing types of bulk mail (for example, subscription newsletters versus unsolicited ads).

However, many Microsoft-hosted e-mail filtering improvements will be delivered by a new add-on service, Advanced Threat Protection (ATP). ATP features protect e-mail users against previously unknown malware as well as malicious URLs and other types of threats. For example, previously unknown malware is filtered by Safe Attachments, which routes all messages and attachments through a behavior analysis environment that uses machine learning and other techniques. Safe Links dynamically blocks links to URLs that are known to be malicious, preventing even redirected links from being opened by users. ATP is currently in preview and will probably start rollout in the third quarter of 2015.