Making Outbound SMTP Non-Authoritative

[gckorn]

We use Postini to filter incoming email from external domains. I now want to filter all intradomain email, i.e., I want all email originating on the server to go to Postini for filtering. Basically, I don't want the outbound smtp server to think that it is authoritative for local domains.

Other than setting up a 2nd mail server, the Postini instructions for a single server solution are cryptically stated as this: "This solution requires the use of two network interface cards or virtual IPs. It is recommended that you create a "jail" which runs a second instance of your MTA."

Has anyone any experience in doing this?

Thanks in advance,
Gary