How it works: Exchange Hosted Filtering

Microsoft has made a big jump into the hosted services game with the introduction of Microsoft Exchange Hosted Services. With a number of services being provided under the "Hosted" umbrella, Microsoft sees these services as another way to boost their bottom line while providing IT services they hope customers will find valuable. In this tip, I'll explain one of these services: Exchange Hosted Filtering.

Exchange Hosted Filtering is a service that provides you with clean mail that has made its way through Microsoft's data centers where it is scanned for viruses and a determination is made about whether or not a particular message is spam. Besides virus and spam filtering, the service also offers these features:

  • Policy enforcement: Provides a mechanism by which a company can granularly monitor both inbound and outbound mail. This can be useful for compliance purposes and can prevent sensitive messages from exiting a company. Policy enforcement can use a number of factors in its efforts, including words and phrases in the message, the size of a message, the kinds of attachments associated with a message, and more.
  • Directory services: Directory services allows you to take action on an incoming messages based on the message recipient. For example, you can indicate that all messages to users that are not on an approved list are to be instantly rejected or designated users should not be subject to any filtering.
  • Disaster recovery: I'm not sure this is really a "feature" since many mail servers already do it, but the Filtering service will queue messages for up to five days in the event that your mail servers are inaccessible.

The Filtering service gives you a way to handle message cleansing tasks without messages having to enter your domain. This can be useful in that you don't waste bandwidth on messages that are marked as spam and you don't have any virus-laden messages hitting your servers in any way. However, the service isn't free. Contact your MS rep for pricing information. Filtering services are also included with the Exchange 2007 Enterprise CAL when you also buy Software Assurance.