This server requires PTR for unauthenticated connections on 10/9/2007 1:56 PM
There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
<adexchange.MLLINDIA.COM #5.5.0 smtp;554 This server requires PTR for unauthenticated connections.>
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bbdoitConnect With a Mentor Commented:
A PTR record (or reverse DNS record) does the opposite of what a regular DNS record does.  For regular DNS, you type in a name and you get an IP address.  For a PTR record, you type in an IP and you get the name.  The format is quite different as each PTR record is formatted as follows:   PTR

Here is a decent explanation:

If you host your own external DNS records then it is possible you may just need to create the reverse DNS zones for your external IP addresses and then create the PTR records.  Unfortunately, even if you do host your own zones you usually need to either ask your ISP to add the appropriate PTR records or have them make sure that you are delegated as the authority for your reverse zones.
I'll need more details on the environment, but the error indicates the server attempting to relay mail does not have a reverse DNS lookup that matches its A record, i.e an IP address that points to the host name.
kishorejohnAuthor Commented:
i am using exchange server 2003 as mail server its  is my DNS Server i am  behind a firewall  
kindly clear me about reverse DNS lookup and A record
Making Bulk Changes to Active Directory

Watch this video to see how easy it is to make mass changes to Active Directory from an external text file without using complicated scripts.

The PTR record is located in the reverse lookup zone in a DNS server. It allows for reverse name resolution using the IP of the record and associating it with the host name in the forward lookup zone.  For example, the A record for adexchange.MLLINDIA.COM resolves its IP address, while the associated PTR record resolves the IP address to the name adexchange.MLLINDIA.COM.
SembeeConnect With a Mentor Commented:
kishorejohn - all of the errors that you have posted as separate questions are probably caused by the same problem - your DNS is not configured correctly. You need to get the server banner, reverse DNS and forward DNS fixed so that everything matches. That will stop the errors.

This is my guide to DNS config for an Exchange server:

Note that the DNS changes are NOT made on your server inside your network, but on public servers.

Put your domain in to and you will see the errors that are generated and how the server looks to the internet.


If your question has been answered, pleased remember to accept the answer and close the question.
kishorejohnAuthor Commented:

Thanks Smion it worked but
i am facing a problem i usually get this error message pls guide
This is an automatically generated Delivery Status Notification.
Delivery to the following recipients has been delayed.

it show me his error but non of them have got they messages
That is a delay message. It doesn't tell you anything about the problem.
It could mean any number of things are wrong, from a simple connectivity issue to a routing problem with the ISP.


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