[Exim] Exim & Postini

Greetings All,

We current user Postini mail and virus filtering for our users.
We have seen a number of virus getting through and after looking at the
headers, the message is not touching postini's servers.

We want to only accept mail from postini's servers. We have the ip
addresses of the primary and backup server. We have tried a few different
configurations to only accept mail from these ip's and it failed.

can somebody shed some light on this for us, how we go about in doing
this?

Thanks!

smk@???