We have an existing mail server. This is our primary. Then we set up Zimbra as second mail server.
Both server's IP are private and are matched to their corresponding public IPs.
The problem is i cant force the Zimbra (mail2.xxxxxxx.net) to not use MTA Relay (Relay MTA for external delivery: mail.xxxxxxx.net port:25).
If i disable this or leave it blank this is what happens;
1) Acounts made by second server can not send mails to the accounts made from the primary server but can receive mails from it. (POP3 ok but SMTP is not ok)
2) I can receive and send mails to Yahoo Mail.
Our concern is that it seems like our Zimbra box is dependent on the primary server (Mdaemon on Windows Server) for its outgoing mail traffic.
What we wanted is that Zimbra must not rely on the primary server so that even if it bogs down, Zimbra can still function.
HOW CAN I FORCE ZIMBRA TO BE INDEPENDENT?
When i leave MTA blank, i cant send mails to the primary server anymore.