MX Record Lookup for Remote Servers

[jdp459]

SOLVED!

Sending Email issue. We can receive fine and can send and receive between our domains without issue.

We recently switched ISP connections. Now a relay is not needed - no relayhost. I think that's where the issue lies.

Running Zimbra 7.1.1 OSE.

When sending, the /var/log/zimbra.log shows that connections to remove servers are to the domain, not the DNS MX record. Huh? I'm wondering what could cause that issue?

For example, an email to a gmail.com address has this in the logfile.
Aug 4 08:16:05 mail postfix/smtp[3832]: connect to gmail.com[74.125.157.18]:25: Connection timed out

But a 'dig mx gmail' shows that the IP used by Zimbra isn't any of the MX records.
;; ANSWER SECTION:
gmail.com. 2754 IN MX 20 alt2.gmail-smtp-in.l.google.com.
gmail.com. 2754 IN MX 30 alt3.gmail-smtp-in.l.google.com.
gmail.com. 2754 IN MX 40 alt4.gmail-smtp-in.l.google.com.
gmail.com. 2754 IN MX 10 alt1.gmail-smtp-in.l.google.com.
gmail.com. 2754 IN MX 5 gmail-smtp-in.l.google.com.

;; ADDITIONAL SECTION:
alt4.gmail-smtp-in.l.google.com. 45 IN A 74.125.77.27
alt1.gmail-smtp-in.l.google.com. 16 IN A 74.125.113.27
gmail-smtp-in.l.google.com. 272 IN A 74.125.47.27

My Zimbra server should attempt to connect with 74.125.47.27, right?

We're running the 'dig' command on the Zimbra server and I can
$ telnet 74.125.47.27 25
to the remote machine and get the ESMTP connection just fine. Did someone, probably me, screw up the postfix lookup config?

$ postconf relayhost
relayhost =

relayhost is empty, so MX record lookups should happen, right?

I thought the issue was with disable_dns_lookups being "yes" and changed it to "no"
postconf -e disable_dns_lookups=no
$ postconf disable_dns_lookups
disable_dns_lookups = no

Then reloaded postfix and checked it again.
$ postfix reload
$ postconf disable_dns_lookups
disable_dns_lookups = yes

YES!? Huh? What?

I'm pretty certain this is a simple configuration issue. I've failed to find a solution searching here and on the postfix forums. Is the antivirus getting in the way?

Thanks for reading.

[phoenix]

Originally Posted by jdp459

We're running the 'dig' command on the Zimbra server and I can
$ telnet 74.125.47.27 25
to the remote machine and get the ESMTP connection just fine. Did someone, probably me, screw up the postfix lookup config?

That isn't really a test of anything other than the server is 'alive', what happens if you run the following (on the zimbra server):

telnet alt2.gmail-smtp-in.l.google.com 25

Have you enabled the "Enable DNS lookups" in the admin UI?

[jdp459]

Just found this in another thread.

-go to global settings>mta tab and check the box for dns lookups
or: zmprov mcf zimbraMtaDnsLookupsEnabled TRUE (zmprov mc zimbraMtaDnsLookupsEnabled TRUE)

I feel so dumb. ;O

[jdp459]

The reason for the telnet was to show that the ISP wasn't blocking port 25. That's all. I wanted to remove and DNS issues, since at the time, it appeared to be the issue (to me).

BTW, thanks for the quick reply. This issue has bothered me for about a day.

[phoenix]

Originally Posted by jdp459

Just found this in another thread.

-go to global settings>mta tab and check the box for dns lookups
or: zmprov mcf zimbraMtaDnsLookupsEnabled TRUE (zmprov mc zimbraMtaDnsLookupsEnabled TRUE)

That's the command line version of the Admin UI setting I mentioned above.

Originally Posted by jdp459

I feel so dumb. ;O

There's no need to, it's easy to overlook a setting. Glad you've fixed it.

[tuaris]

Why is that even an option? For what possible reason would anyone want to disable it?

[phoenix]

Originally Posted by tuaris

Why is that even an option? For what possible reason would anyone want to disable it?

Split Domain.