Messages from Edge MTA to Zimbra goto the junk folder

[swhitman]

I have noticed that sometimes email from an employee in the company to another employee will sometimes go to the junk folder. This seems to happen when using an email client from a computer at home. Looking at the SPAM information in the header it seems that the problem occurs because the ISP's IP address causes a high SPAM score to be used.

We have an edge MTA in use. Employees must authenticate with it in order to send email. When users authenticate with the edge MTA many of its anti-spam measures are bypassed.

Is there any way to pass to the Zimbra server information that the sender of the email has been authenticated by the edge MTA? Or is there documentation on a better way to use Zimbra and an edge MTA?

Because of this problem I have considered getting rid of the edge MTA. But on the other hand I like having a separate server where I can setup things like F-Prot AV and grey-listing without having to disturb the stock Zimbra configuration files.

Thanks.
Stu

[swhitman]

I have white listed mail from our domain in Zimbra. Our edge MTA enforces SPF so any mail from our doamin must originate from our server. That, along with the authentication, should make white listiing mail from our domain safe.

Should I handle this another way? If not, is there a way to preserve this configuration across Zimbra updates?