Zimbra using wrong MX of destination domain

[rock_it]

HI All

I have a new Zimbra install, currently running on a dummy domain.

I am sending a test email to our company's established email domain.

This email domain has 4 MX records: Pref 10,20,50 and 100.

The last preference MX server, 100, actually is not working at the moment.

But Zimbra has decided that it wants to use said MX, the final preference.

Can anyone explain why Zimbra would:
a) Make an initial send attempt using the last preference MX server, and
b) Why is it not, upon rejection, trying the other MX servers?

I am evaluating Zimbra, and so far have had much pain, particularly with the Demo applicance version, so I am now trying the open source version on top of Ubuntu 11. God knows what the demo appliance was doing...

Cheers
Michael

[Klug]

Welcome to the forum.

Is the DNS used by your Zimbra server working correctly?

From the Zimbra server itself, from command line, are you getting the four MX with this command:

dig mx yourdomain.tld

[rock_it]

(At least with Ubuntu, I have a handle on the OS, if not Zimbra. The 'Appliance' was not straight forward by any means, and IMHO is a PR disaster. Or perhaps it is intended for Unix admins?? :P )

[rock_it]

Hi mate, thanks for the reply.

Yes the DNS works, it is the main DNS server.

I am not using a local bind installation, I simply created a test domain on my main DNS server.

Dig mx:
;; QUESTION SECTION:
;xxxxxxzimbra.local. IN MX

;; ANSWER SECTION:
xxxxxxzimbra.local. 3600 IN MX 10 linuxubuntuzimbra.<maindomain>.local.


But I don't think that is the point: The test message is to an external domain... It found the domain fine, it just made the mistake of using the wrong MX (according to the Queue logs)

FYI, now that I have set Zimbra to use my existing MTA, it works. But still, I want Zimbra to be capable of doing it itself..

[rock_it]

Oh now this is embarrassing.

I think it's just my network.

The last preference MX was simply the last resort and therefore the one that got logged.

I should have more faith.

Can I ask, what is the best way in ZImbra to track SMTP communication?
We are only a small network, so it is feasible to be able to 'watch' smtp communications, i.e in an active window of some sort.

Cheers
Michael

[phoenix]

I guess thes questions are about ZCS not Zimbra Desktop (where you've posted) so I'll move it to the correct forum.

Originally Posted by rock_it

Can I ask, what is the best way in ZImbra to track SMTP communication? We are only a small network, so it is feasible to be able to 'watch' smtp communications, i.e in an active window of some sort.

Tail the log file and you'll see what's happening.

[rock_it]

Thanks pheonix.

Looks likes there is plenty of logs for diagnosis

[phoenix]

Originally Posted by rock_it

This email domain has 4 MX records: Pref 10,20,50 and 100.

The last preference MX server, 100, actually is not working at the moment.

But Zimbra has decided that it wants to use said MX, the final preference.

The Zimbra server doesn't arbitrarily decide to use a specific MX, it merely does a DNS lookup and uses the response it gets from the DNS server.

Originally Posted by rock_it

Looks likes there is plenty of logs for diagnosis

I'd suggest you go to the Split DNS article and run (on the Zimbra server) all the commands in the 'Verify section of that article - that will give you a starting point for checking the DNS.

[rock_it]

Originally Posted by phoenix

The Zimbra server doesn't arbitrarily decide to use a specific MX, it merely does a DNS lookup and uses the response it gets from the DNS server.

Yes, and it should use MX based on preference value.

Originally Posted by phoenix

I'd suggest you go to the Split DNS article and run (on the Zimbra server) all the commands in the 'Verify section of that article - that will give you a starting point for checking the DNS.

That information relates to the local DNS setup for the local MX.

My issue had nothing to do with my own MX records. It was public email domain, one which has nothing to do with the entries I place in my BIND/MS DNS server.


Zimbra DID the correct thing: It tried 10, the 20, then 50, then 100. 100 was the last to fail, and so it was the one that got reported.

MX record - Wikipedia, the free encyclopedia
"<mail server>.. does an MX lookup for the domain name, it gets a list of servers and their preference numbers. The smallest preference number has the highest priority and any server with the smallest preference number must be tried first"

Cheers
Michael.

[phoenix]

Originally Posted by rock_it

Yes, and it should use MX based on preference value.

It does exactly that and the response is given by the DNS server, it's not any choice that Zimbr makes.

Originally Posted by rock_it

That information relates to the local DNS setup for the local MX.

Really? Thanks fo pointing that out but I know that already.

Originally Posted by rock_it

My issue had nothing to do with my own MX records. It was public email domain, one which has nothing to do with the entries I place in my BIND/MS DNS server.

I understand that but I wanted to see the information that all those commands gave.

Originally Posted by rock_it

MX record - Wikipedia, the free encyclopedia
"<mail server>.. does an MX lookup for the domain name, it gets a list of servers and their preference numbers. The smallest preference number has the highest priority and any server with the smallest preference number must be tried first"

Thanks for the tutorial and, yet again, for pointing out something I already know.