[SOLVED] MX record confusion (moving to an external mail system)

elliot01 · 01-05-2014, 05:19 AM

Hi all,

I would be so grateful if some kind soul could point out what I am missing here!

We have an internal mail server. MX records for the domains it manages were all configured internally/externally and all has been fine for four or five years.

Recently we have switched to Gmail, so I have changed the MX records on all three of our internal DNS servers (Active Directory) and also on our ISP. This was all done on 24th Dec, so plenty of time has passed for full propagation.

Now... most of our emails are coming through fine, but we have some examples when they just do not.

For instance, I have a linux box on our network, which produces some HDD capacity reports. It uses a simple "mail -s" command to mail the report to server.reports@hayley-group.co.uk.

Instead of the linux box looking up the MX for our domain and sending the mail through Google, it continues to send the mails through our old mail server.

If I manually do an MX lookup on the same linux box, it looks fine:

Code:

[root@hayley etc]# nslookup -query=mx hayley-group.co.uk
Server:         10.11.1.217
Address:        10.11.1.217#53

hayley-group.co.uk      mail exchanger = 10 aspmx3.googlemail.com.
hayley-group.co.uk      mail exchanger = 10 aspmx2.googlemail.com.
hayley-group.co.uk      mail exchanger = 5 alt2.aspmx.l.google.com.
hayley-group.co.uk      mail exchanger = 5 alt1.aspmx.l.google.com.
hayley-group.co.uk      mail exchanger = 1 aspmx.l.google.com.

Where is the best place to start looking into this? Why is this linux box routing the mail through the old server, when I can successfully resolve MX to Google's servers?

Any help or guidance appreciated!

Best Regards,

Elliot

Ser Olmy · 01-05-2014, 05:23 AM

Quote:

Originally Posted by elliot01

Where is the best place to start looking into this? Why is this linux box routing the mail through the old server, when I can successfully resolve MX to Google's servers?

The mail command uses the local MTA to deliver mail. Perhaps the MTA is configured to use the old, internal server as a Smart Host? Or there could be a mailertable entry overriding the information in the MX records.

What is the local MTA on the affected box? (Postfix, sendmail, something else entirely?)

elliot01 · 01-05-2014, 05:25 AM

Bleh, that's it! I was overlooking something rather obvious!

I checked /etc/postfix/main.cf and there was a relayhost configured, pointing to the old mail server. Changed it and now working - bingo!

Thank you