[SOLVED] Exchange and Zimbra behind NAT

[bryan08]

We have Zimbra 5.05_GA on Ubuntu 6.06 LTS running great on our network with Exchange Server 2007. One problem that I am having is that when I send email from Zimbra to Exchange account, the email gets deferred.
Zimbra local ip : 192.168.0.111
Exchange local ip: 192.168.0.118
I have already setup internal dns server.

The error under /var/log/zimbra.log shows
Jun 5 15:59:09 localhost postfix/smtp[28543]: 609964582C1: to=, relay=none, delay=19560, delays=19522/0/38/0, dsn=4.4.1, status=deferred (connect to mail.exchangedomain.org[xx.xx.xx.xx]: Connection timed out)

xx.xx.xx.xx = external ip
dig mail.exchangedomain.org gives external ip.
I also updated /etc/hosts
127.0.0.1 localhost.localdomain localhost
192.168.0.111 mail.zimbradomain.org
192.168.0.118 mail.exchangedomain.org

I don't want to disable the dns lookups as we need to send external emails.
I would appreciate if someone can point me in the right direction.
Thank you in advance.

[phoenix]

Have you set-up a Split Domain for this configuration? You will need that for correct routing of email.

You also need to remove the entry in your /etc/hosts file for the exchange server, it's not needed.

[bryan08]

Thank you for your prompt response. I think I forgot to say this. The Exchange and Zimbra has its own external ip web address, MX and A values. We are not trying to make Zimbra as our primary or secondary email server. Some of our users need to able to email users on exchange server.
$ zmprov md exchangedomain.org zimbraMailCatchAllAddress @exchangedomain.org
ERROR: account.NO_SUCH_DOMAIN (no_such_domain: exchangedomain.org)

[Bill Brock]

Adding the LAN IP's of the servers to the other one's HOSTS file may solve your problem After doing so, each machine will resolve to the other using the entry in the HOSTS file and not the DNS server. By default, most operating systems will check the HOSTS file before checking their assigned DNS server. This can be changed of course but it is usually the default configuration.

[bryan08]

My /etc/hosts file looks like this
127.0.0.1 localhost.localdomain localhost
192.168.0.111 mail.zimbradomain.org mail
192.168.0.118 mail.exchangedomain.org

/etc/host.conf
order hosts,bind
multi on

I am still getting this error message under /var/log/syslog
Jun 5 15:59:09 localhost postfix/smtp[28543]: 609964582C1: to=, relay=none, delay=19560, delays=19522/0/38/0, dsn=4.4.1, status=deferred (connect to mail.exchangedomain.org[xx.xx.xx.xx]: Connection timed out)
where xx.xx.xx.xx = external ip
Also, hosts file is updated on the exchange server.
192.168.0.111 mail.zimbradomain.org

[Bill Brock]

If you ping mail.exchangedomain.org on the machine with the error what IP does it ping.

[bryan08]

It pings with external ip and there is no reply.

[Bill Brock]

It should be resolving to what is in the HOSTS file. Very odd. I know in Windows there is no need to reboot after changing the HOSTS file. Don't know about Linux.

[phoenix]

It pings with external ip and there is no reply.

That would explain your problem. From the ZImbra server try a dig:

dig exchangedomain.org mx
dig exchangedomain.org any

and see what response you get.

[bryan08]

I get:
dig: '.exchangedomain.org' is not a legal name (empty label)

I don't understand why it's not taking the local ip from hosts file. Do I have to edit route file or anything? Appreciate your help, Bill.