Sendmail as Primary MX, Zimbra as Secondary
We want to utilize a Sendmail server as our primary MX which will function as a spam filter and also for spooling email when Zimbra is offline for maintenance. Sendmail is configured to forward mail for our domain on to the Zimbra MX record specified in the mailertables file. We are having problems getting this to work. What settings if any need to be configured in Zimbra to get this to work. As a side note, I know the forwarding from Sendmail is working at least to another test server we have. What gives?