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Reverse DNS PTR record

Posted on 2007-11-28
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Last Modified: 2012-06-21
I have a client that is having emails to AOL email addresses bounce.  I have read about why this may happen with AOL and it seems to be related to them not accepting email from domains that do not have PTR or SPF records setup for a reverse DNS zone.  I called the ISP of my client and had them setup a PTR record and it has propagated.  I sent a test email from that domain to an AOL account and it has been about a half hour and the email has not been delivered nor has it bounced.  If I went to setup the SPF record do you think that would fix the issue.  It appears that this only happens with AOL accounts.
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Question by:pcmb
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9 Comments
 
LVL 21

Expert Comment

by:from_exp
ID: 20368742
does your ISP have correct TTL set for that IP address.
some antispam companies like sorbs asks for valid PTR AND TTL set to be greater than 43200
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LVL 16

Expert Comment

by:2PiFL
ID: 20368880

I had to add a SPF record to get mail to AOL.  If you need help here is a good Wizard:
http://www.openspf.org/wizard.html 
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LVL 1

Author Comment

by:pcmb
ID: 20368981
The TTL is set to 86400.  However, the PTR record resolves to the public IP of the domain in question but it gives an error because the A record is resolving elsewhere because they subscribe to an MX spam filtering service.
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Expert Comment

by:brakk0
ID: 20368982
I had the same problem with PTR records and AOL, but I don't think they require SPF records (since so many sites are not using them yet).

I would say just wait a day or so and try it again. It may take more than a half hour for their cache to clear out.
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LVL 21

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by:from_exp
ID: 20369490
I would agree with brakk0, to wait for a day.
Normally 24 hours are enough for dns to renew all cache entries
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LVL 31

Expert Comment

by:moorhouselondon
ID: 20377280
Just to confirm brakk0's comment.  SPF is definitely not mandatory to successfully send emails to AOL.  However, if AOL operate a scoring system for assessing acceptability, then it would surely help to have SPF.  Plus in the future the goalposts will move.
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Accepted Solution

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jwr51 earned 250 total points
ID: 20438482
For those who need a quick fix, AOL and Craigslist will accept Exchange emaill without a valid reverse DNS record if you route your Outbound mail through a valid email account with a recognized ISP. Read this link - http://www.amset.info/exchange/smtp-connector.asp.
I use my account at sbcglobal.net which has an Outbound mail server at smtp.att.yahoo.com.
You need to set your email login details on the SMTP Connector/Advanced/Security page.
I am still trying to get a valid reverse DNS pointer from AT&T but I have heard that this may not help if you have a DSL connection.
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Expert Comment

by:jwr51
ID: 22805736
The Reverse PTR Red Herring.
I added SPF records to my GoDaddy DNS records and have successfully sent mail to AOL, and Hotmail from a private Exchange Server. Before I added the SPF records, mail to AOL and Hotmail was being returned as undeliverable. See attached file for my GoDaddy DNS records.
GoDaddy-MX-SPF.pdf
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LVL 31

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by:moorhouselondon
ID: 22806429
It did not used to be mandatory, the Goal Posts must therefore have moved.  See my comment about "scoring" above.  The "weighting" of Reverse PTR in that scoring "mix" will however - currently, at least IMO, be "heavier" than SPF, purely because adoption of SPF currently is much lower.
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