In our comparative test we examined products that archive messages across the local network, but we must note that there are a plethora of hosted e-mail archiving services from Microsoft, MessageLabs and LiveOffice, as well.

These services can offer some major advantages. For example, if you are currently using an off-site antispam service and the company also offers archiving, the combination is easy to integrate. However, this configuration won't archive internal e-mail unless you set up a proxy system that forwards all internal e-mail through the service. Hosted solutions also offload considerable bandwidth from both your internal network and your Internet connection because replication of e-mail is handled off-site. Finally, off-site networks may have more highly available systems than your local network, because most providers have at least two Internet connections and multiple servers in a load-balancing configuration to handle archiving processes.

While we did not review those services, we did manage a hands-on look at Proofpoint's Email Archiving 3.0 (a product the company picked up with its Fortiva acquisition) which takes a hybrid approach to the message archiving issue: an on-site appliance is used to archive messages to an off-site storage system.

The appliance was configured in our LAN in much the same way as the other archiving solutions, but rather than messages being archived locally in an SQL database, they were sent to Proofpoint's hosted database across the Internet.

The Proofpoint MLX offers the benefits of on-site interception of all e-mail for the archive along with the scalability, resilience against disaster, and availability to high-performance storage and indexing servers typical of the services in this market. Setting up the appliance locally is a process similar to the products reviewed in this test in that it requires setting up service accounts and groups, configuring Exchange journaling and testing connectivity with the Proofpoint system. The process was well documented, and installation support is included in the price of the product.

This system is set up by default to archive only incoming e-mail, rather than to archive an existing e-mail store. This is a philosophical design issue rather than a technological one. You could push a full archive but archive speed would be limited by your Internet connection and not the archiving product. Proofpoint argues that because old e-mail could have been altered before the archiving processes were instigated; it is a worthless process to archive an old store for e-discovery purposes because you cannot prove that those messages were archived in an unaltered state.