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Help with DNS/MX record

Posted on 2009-12-29
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Last Modified: 2012-05-08
I have a domain set up with the following DNS record.  In certain situations however, email is not received by the server, and instead the sender receives a Delivery Failure ():
When I test the domain name with intoDNS, I get the following errors:

MX CNAME Check
WARNING: CNAME was returned for the following MX records:
mail.mydomain.co.uk
The CNAME(s) that were returned are listed above. This is not ok per the RFCs and can cause problems including mail being lost!

MX A request returns CNAME
WARNING: MX records points to a CNAME.
CNAMEs are not allowed in MX records, according to RFC974, RFC1034 3.6.2, RFC1912 2.4, and RFC2181 10.3. The problem MX record(s) are:
mail.mydomain.co.uk points to ['mydomain.co.uk']
This can cause problems

The server is a web server that also has email server software installed, so its acting as two roles.
Here's the DNS settings.  I would be very grateful if anyone could suggest how they could be fixed.

-------------------------------------------------------------------------
mydomain.co.uk.  300  IN  SOA  ns.rackspace.com  hostmaster.rackspace.com  (
1262099971
86400
7200
604800
300
)
mydomain.co.uk.  300  IN  A  89.234.xxx.xxx
mydomain.co.uk.  300  IN  NS  ns.rackspace.com.
mydomain.co.uk.  300  IN  NS  ns2.rackspace.com.
mydomain.co.uk.  300  IN  MX  10  mail.mydomain.co.uk.
www.mydomain.co.uk.  300  IN  CNAME  mydomain.co.uk.
ftp.mydomain.co.uk.  300  IN  CNAME  mydomain.co.uk.
mail.mydomain.co.uk.  300  IN  CNAME  mydomain.co.uk.
-------------------------------------------------------------------------
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Question by:Rouchie
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12 Comments
 
LVL 76

Accepted Solution

by:
Alan Hardisty earned 1600 total points
ID: 26139461
Your MX record should point to an IP address not another FQDN.
Please change it to an IP and then you should be fine.
0
 
LVL 76

Expert Comment

by:Alan Hardisty
ID: 26139463
e.g., mail.mydomain.co.uk 300 IN A 123.123.123.123
0
 
LVL 74

Assisted Solution

by:Glen Knight
Glen Knight earned 400 total points
ID: 26139492
You need to create an A record for mail.domain.com instead of a CNAME record.
When setting up the A record point it to the public IP of your Exchange server to find out what that is goto http://whatsmyip.org

it's not good practice to setup MX records to point to IP addresses and some ISP's won't let you.
0
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LVL 25

Author Comment

by:Rouchie
ID: 26139493
Hi Alan, that's the fastest response I've had on EE - thanks!

Let me make the changes and get back to you...
0
 
LVL 25

Author Comment

by:Rouchie
ID: 26139512
Hi guys.  Following on from both your input, here's the new record.  Does this look okay or does the MX part need altering also?

mydomain.co.uk.  300  IN  SOA  ns.rackspace.com  hostmaster.rackspace.com  (
1262107784
86400
7200
604800
300
)
mydomain.co.uk.  300  IN  A  89.234.xxx.xxx
mail.mydomain.co.uk.  300  IN  A  89.234.xxx.xxx
mydomain.co.uk.  300  IN  NS  ns.rackspace.com.
mydomain.co.uk.  300  IN  NS  ns2.rackspace.com.
mydomain.co.uk.  300  IN  MX  10  mail.mydomain.co.uk.
www.mydomain.co.uk.  300  IN  CNAME  mydomain.co.uk.
ftp.mydomain.co.uk.  300  IN  CNAME  mydomain.co.uk.
0
 
LVL 76

Expert Comment

by:Alan Hardisty
ID: 26139519
Sorry about that - always happy to respond quickly if physically able to.  Glen - you gotta be faster!
Alan
0
 
LVL 25

Author Comment

by:Rouchie
ID: 26139528
I'm guessing these changes might take a couple of hours to filter into the intoDNS checks, so I'll leave for a while and run the test again later...

Thanks again.
0
 
LVL 76

Expert Comment

by:Alan Hardisty
ID: 26139543
Yes - they will take a while to ripple around the world  24-48 hours usually, but that looks a whole lot better.
Check on http://www.mxtoolbox.com/diagnostic.aspx - it should query live info and should come back okay,
0
 
LVL 74

Expert Comment

by:Glen Knight
ID: 26139545
Looks good! It can take upto 48 hours on some systems but your more likely to see it working within a few hours.
0
 
LVL 74

Expert Comment

by:Glen Knight
ID: 26139560
Sorry Alan but I am at a distinct disadvantage can only type on the iPhone with a maximum of 2 thumbs!!

Either way it looks like the author is sorted and that's the important thing!
0
 
LVL 74

Expert Comment

by:Glen Knight
ID: 26139779
Author > please don't award any points for my posts alanhardisty already had it covered I was just too slow off the mark! :-)
0
 
LVL 25

Author Comment

by:Rouchie
ID: 26143944
Thanks.  I'll split the points in favour of alanhardisty, as it was useful to have additional clarification.
Anyway there'll be another question to follow shortly... :-/
0

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