Google™ Postini Services is a known provider of mailfiltering, archiving and encryption solutions. You may want to keep using their services along with Smarsh Hosted Services's Hosted Exchange.

The following conditions are required to use Postini together with Smarsh Hosted Services services:

  1. The MX records for your domain name point to Postini's servers. Read the Knowledge Base article on What Is An MX Record? What Is The Correct Syntax For MX Records? What Is Priority?
  2. Mail forwarding is set up from your Postini account to Smarsh Hosted Services's MX records.

Important note: Postini account should be set up to use a Privately Managed Password (PMP), since it can not validate against the hosted domain using its built-in POP validation method.

You can contact Postini Support to get help on managing Postini account.