Ive installed zimbra on an ubuntu server. Seems to work great but I cannot receive mail unless i turn off dns lookups in zimbra. Then, i can receive mail fine but cannot send.

In looking at the zimbra wiki it states the steps to check your domain and server MX and A records with 'host -t mx' and 'host -t a'. We did these and additionally went to dnsreports.com and everything looks perfect. Is there something else we can check to see whats going on?

fyi in the zimbra admin console i can see the incoming emails being deferred because the connection is refused. Zimbra sits on the same physical box as the host the records are pointing to.

I would greatly appreciate any help.