For users configured within the Email Continuity service, this solution works by sending a copy of each email directed to the MX failover service to Webmail access accounts.  You can access the Web- based emailing interface from anywhere in the world, or just continue to use the email client from your office as if no interruption were occurring in your mail server by pulling the messages from the Email Continuity accounts via POP3.

The Postini Anti-Spam/Virus filtering system of your choice filters all incoming messages for your domain regardless of your primary mail server status.  If Postini can not deliver incoming messages to your mail server, they are sent to Webservio's MX Backup service where they are held and copied to the Email Continutiy service.  Configured users can access these emails and respond to them as needed.

When sending emails from the Email Continuity accounts,  correspondents will see the messages are coming from your domain rather than Webservio’s stand by email system.  We also apply SmartHost technology to send a copy of each message sent from this system back to the MX failover service.  As a result, a complete email history is ultimately delivered to your primary mail server when it becomes available.Optionally, by utilizing Postini's dual delivery feature, a “mini-archive” of messages can be stored in each user's Email Continutiy inbox.  This creates a convenient history for users to work from during primary mail server downtime.  In addition, contacts may be exported from email clients (Outlook, Thunderbird, etc.) in Vcard format and uploaded to individual Email Continutiy accounts.  These  features ensure end-users are not “in the dark” when continuing email communications during primary mail server failure.

Google Message Continuity - How It Works

Essentially all email is synced between Exchange and Gmail and, if the Microsoft solution becomes unavailable for whatever reason, users can simply switch to Gmail and continue work.This is also true for calendar and contacts data. Dubbed Google Message Continuity, it's a product of the Postini acquisition from 2007.

"Google Message Continuity is a cloud-based email continuity solution—a service that helps to ensure that you always have access to your email," Rajen Sheth, Group Product Manager for Google Apps, wrote.

"Google Message Continuity works by replicating email accounts hosted on Microsoft Exchange Servers in the cloud, using Gmail, Calendar and Contacts," he said.

"If the Microsoft Exchange sever fails, or requires scheduled maintenance or downtime, all you have to do is log into Gmail and continue regular, up-to-date email communication through Google," he added.

"Since Gmail and Microsoft Exchange are constantly synchronized with each other, you can seamlessly switch from one email environment to the other," he explained.