AOL mail stuck in queue.  Client is not on blacklist, rDNS checks out, MX record correct

Posted on 2011-03-08
Last Modified: 2012-05-11
We have an issue with mail to AOL getting stuck in the queue.  I have tried all the steps listed in AOL's troubleshooting page.  There was an ongoing thread between the AOL recipient and a member of the Exchange organization, and out of the blue the messages began building up in the queue.  There is nothing in the queue folder in the EXCHSVR folder.  Here are the results of the tests:
nslookup -q=mx
Non-authoritative answer: MX preference = 15, mail exchanger = MX preference = 15, mail exchanger = MX preference = 15, mail exchanger = MX preference = 15, mail exchanger =    internet address =    internet address =    internet address =    internet address =    internet address =    internet address =    internet address =    internet address =    internet address =    internet address =    internet address =    internet address =    internet address =    internet address =

They are not any blacklists.  
When I perform a telnet:
421 4.7.1 : (DNS:NR)

Connection to host lost.

I've checked rDNS, confirmed their MX record, IP address, etc...  Any ideas?
Question by:szagoria
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LVL 76

Expert Comment

by:Alan Hardisty
ID: 35073359
From the link you posted:

421 DNS:NR
The Reverse DNS lookup for your IP address is failing. This could be a transient issue. Confirm the IP that sends your mail. Then check the rDNS of that IP using our troubleshooting tools. If it passes, please wait 24 hours and re-try before opening a support request.
rDNS must be in the form of a fully-qualified domain name. rDNS containing are not acceptable, as these are merely placeholders for a valid PTR record. rDNS consisting of IP addresses are also not acceptable, as they do not correctly establish the relationship between domain and IP address.
rDNS that may be similar to dynamic IP space (containing pool, dhcp, dyn, etc.) may be treated as suspect, and should therefore should be changed to reflect a fully-qualified domain name with standard reverse DNS.

What is your IP Address that you send mail from?  Please post it (I will hide it) and check it for you.


Author Comment

ID: 35073528
I checked rDNS, everything came back OK.  That's why I can't understand what problem AOL is having.

Author Comment

ID: 35073804
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LVL 76

Expert Comment

by:Alan Hardisty
ID: 35073832
I don't like the look of your SPF record, but the usual test site I use isn't working happily.  Could you please send me a test email to alan @ so I can see what my Anti-Spam software makes of it.



Author Comment

ID: 35074068
Update:  Messages to AOL are getting out, but they are VERY slow.  If I click refresh every once in a while the number of messages (now 5) will change.  I can tell that there are different messages in the queue, but they seem to go out at random.
LVL 76

Accepted Solution

Alan Hardisty earned 500 total points
ID: 35074088
Okay test email received and my software doesn't think your SPF record is good.

Can you please review it and correct it.

You can use to work out what you should have.

I usually use to test the record but it seems to be playing up tonight.

Any problems - please let me know.


Author Closing Comment

ID: 35150589
Worked.  Within 12 hours all the queues emptied and recipients were receiving their email.  Thanks!

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