If you are using Postini as a spam filter before hitting your CPanel SMTP server (which I highly recommend!), here are a couple tidbits to get it working properly.
- Be sure to uncheck "Always accept mail locally even if the primary mx does not point to this server. " under the "Edit MX Entry" on a domain in WHM (WebHost Manager).
- Under the "Exim Configuration Editor" in WHM, go to "Access Lists", the to "Whitelist: Trusted Mail Hosts/Ip Blocks (bypass all smtp time checks except recipient verification)".
Make sure this box is checked. Now click "EDIT". Put this into your Trusted Mail Hosts (Whitelist).
64.18.0.0/20
207.126.144.0/20
Click "Save" on the "Trusted Mail Hosts" screen, and "Save" on the "Exim Configuration Editor".
Those two things should definitely help get your Postini install going
