I installed Zimbra as alternative to Exchange 2007.
For the time of conversion I would like to keep both system parallel with different domain names.
Users in both domains can send and receive emails to/from Internet.
Zimbra Users has no problem sending emails locally (Same LAN subnet) to Exchange but Users in Exchange can't send email locally to Zimbra Users.
From Exchange Server I can:
telnet Zimbra on port 25 and sent email to the user
nslookup return proper Zimbra internal MX record
I'm using MS DNS servers.
Does anybody known what I'm missing?