Need help understanding how DNS works with Zimbra from behind a firewall
I've been reading and searching for days and do not grasp how to resolve this issue. DNS is obviously something I need to study up on.
I am moving a Zimbra server to a new datacenter where it will be behind a firewall for the first time.
When I moved this server to the new datacenter and reconfigured for the new IPs, everything 'seemed' to work:
All mail was received.
Mail could be sent out.
All web interfaces functioned, mail and admin.
The problem was that mail was received into the queue, but it would NOT deliver to the mailboxes. Research indicated that being behind a firewall now the mail server needed a local DNS server that would resolve the names to the local subnet IP. They said to add an A record and PTR for the mail server. There is a Microsoft DNS server on the subnet.
The PTR records were easy and work fine. However I am not grasping something in getting the A record entries right.
Zimbra Hostname: mail.myserver.com
The DNS server is: localdns.net
If I add an A record of mail.myserver.com pointing to 10.xx.xx.30, it becomes mail.myserver.com.localdns.net.
Running "host mail.myserver.com" yields the public IP, not the local subnet IP.
Running "nslookup mail.myserver.com" from inside a Windows server on the same subnet returns the proper local subnet IP of 10.xx.xx.30.
Modified resolve.conf to: nameserver 10.xx.xx.56 (the MS DNS Server)
Any help appreciated.