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exchange not able to e-mail to AOL

I have a new client that i am visiting Wednesday. They are not able to e-mail AOL users from there exchange server? They are not black listed. What can I do to resolve this?
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Hi zenworksb,

Do they get any bounce messages? If so they might need to set up a reverse DNS record. AOL are quite stringent on the requirements for sending to their email servers.

Good Luck,

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check and make sure your exchange server is able to be resolved in a reverse DNS lookup.

In the reverse dns lookup field, enter the exchange server (or external IP for the eschange server) and it should show up as the fully qualified domain name. For example if you enter and it resolves as then tht is not the problem. However if you enter and the page says there is no PTR record for that address, then the lack of reverse DNS is most likely your problem.

Getting a PTR record added can be difficult depending on how the server is hosted or what kind of internet connection it sits on. If it is hosted by a thrid party that handles all the hosting from end to end (ie www site, mail server and DNS) then call and ask them to enter a PTR record for the DNS entry that corresponds to the Exchange server.

However, if it is hosted in house and you use Cox, Verizon or another ISP, you will have to get the ISP to host the PTR record even if you have your own external DNS server. This is because when a (forward) DNS request is made, it finds your inhouse external DNS based on the authoritative DNS address for your domain, but when a reverse DNS lookup happens, it starts with the address, not the name, and the address is leased to the ISP that is providing the bandwidth. Therefore the ISP would have to have a PTR record in addition to your authoritative DNS server.

I had to do this exact fix with one of my customers who had their own web, dns and mail server hosted in house. Their ISP had to host the PTR record for it to work to AOL's satisfaction. They were then able to send mail to addresses.

Personally, I thought my answer was far more robust than the first two posts...

I was initially going to recommend that Sembee get all the points, read the link he posted - he wrote it specifically for this problem, and it works perfectly.

His was the first "robust" answer here, and knowing from experience that it works, any other suggestions were moot.

I recommended a split with InteraX because they pegged they fact that it was most likely caused by an invalid PTR record, and stated the well known fact that AOL are incredibly picky (reinforced by Sembee, posting the AOL postmaster link)

None of this matters though, as the Asker returned and made their own decision - Accepting Sembee's answer

Works for me, and it is the askers decision, after all.