Reverse DNS does not match SMTP Banner

Dercio Tembe
Dercio Tembe used Ask the Experts™
on
Hello, I have a new server that I finish configiuration of exchange server 2010.
When I do the test on mxtoobox.com I getthis message:
Reverse DNS does not match SMTP Banner
And I'm not able to send email for some domains. Also nobody cannot send email to my domain.
Can you help me on this issue please?

Thanks!
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Network Architect
Commented:
Have you checked if its created a reverse dns lookup for : mail.company.com/your exchange server ?

Or maybe you need to update it. check your dns/domain servers if its correct there.

Commented:
If you have a static IP that you are using to send out mail, then you can ask your ISP to configure a PTR record for your Exchange server (same as the MX record name.

http://www.crucialp.com/resources/tutorials/web-hosting/how-reverse-dns-works-rdns.php

If you have dynamic IP, then you should use the ISP's SMTP server as a Smart Host to send mail from your Exchange server. You set this in the Send connector's properties.

You can also use this method if you have a Static IP

-Ninjatek
Top Expert 2011

Commented:
Reverse DNS does not match SMTP Banner
This is not a fatal error nor is it a requirement, but something that should be configured if possible to increase the chances of your mails landing in the recipients inbox.
And I'm not able to send email for some domains.
This could be related to the rdns not matching your banner, but it could also be several other things.  Do you have any NDR's for those mails or preferably the headers from one of those same mails that does get delivered?
Also nobody cannot send email to my domain.
This is completely unrelated to reverse DNS of your sending server (not) matching it's banner.  Do you have MX records setup for your domain?  Do the MX record targets have valid A records?  Did you do an SMTP test on mxtoolbox.com?  Have you checked out https://www.testexchangeconnectivity.com ?
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Dercio TembeIT Assistant

Author

Commented:
I have the Reverse DNS configured. The Pointer is also configured.
When I do test of exchange connectivity SMTP outbound it send email to some domain. but cannot send to gmail, hotmail, etc..
Sudeep SharmaTechnical Designer

Commented:
Did you try to do telnet to any of MX of gmail.com or hotmail.com and see what error do they give you while sending the email to them and at what stage? At connecting, or while typing rcpt to: etc....

Sudeep
Top Expert 2011

Commented:
Paste the headers from one of your mails that gets delivered.
Dercio TembeIT Assistant

Author

Commented:
Now I can send mail to gmail.com and other domains, but still when I send to hotmail I get this undelivered message header:

SNT0-MC4-F28.Snt0.hotmail.com rejected your message to the following e-mail addresses:
dercioneves@hotmail.com (dercioneves@hotmail.com)
SNT0-MC4-F28.Snt0.hotmail.com gave this error:
OU-001 (SNT0-MC4-F28) Unfortunately, messages from 41.220.160.50 weren't sent. Please contact your Internet service provider since part of their network is on our block list. You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors.
A problem occurred during the delivery of this message to this e-mail address. Try sending this message again. If the problem continues, please contact your helpdesk.

Diagnostic information for administrators:
Generating server: cs-exch01.oneun.org.mz
dercioneves@hotmail.com
SNT0-MC4-F28.Snt0.hotmail.com #550 OU-001 (SNT0-MC4-F28) Unfortunately, messages from 41.220.160.50 weren't sent. Please contact your Internet service provider since part of their network is on our block list. You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. ##
Original message headers:
Received: from cs-exch01.oneun.org.mz ([::1]) by cs-exch01.oneun.org.mz
 ([fe80::d8de:ca06:65a4:82bb%10]) with mapi; Wed, 7 Dec 2011 15:30:20 +0200
From: Dercio Tembe <dercio.tembe@oneun.org.mz>
To: "dercioneves@hotmail.com" <dercioneves@hotmail.com>
Subject: Mail Server Test
Thread-Topic: Mail Server Test
Thread-Index: Acy05F23jVVY+IzMRzKUhaXbuwOyOA==
Date: Wed, 7 Dec 2011 13:30:20 +0000
Message-ID: <338ACE2C286D784BA3B314F784EBFF2D0C34D4D0@cs-exch01.oneun.org.mz>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
Content-Type: multipart/alternative;
      boundary="_000_338ACE2C286D784BA3B314F784EBFF2D0C34D4D0csexch01oneunor_"
MIME-Version: 1.0
Dercio TembeIT Assistant

Author

Commented:
Also when I go to www.testexchangeconnectivity.com and test for Inbound mail I got these errors below:

Testing inbound SMTP mail flow for domain dercio.tembe@oneun.org.mz.
ExRCA failed to test inbound SMTP mail flow.

Testing Mail Exchanger cs-exch01.oneun.org.mz.
One or more SMTP tests failed for this Mail Exchanger.


Attempting to send a test e-mail message to dercio.tembe@oneun.org.mz using MX cs-exch01.oneun.org.mz.

Delivery of the test message failed.
Additional Details
The server returned status code 550 - Mailbox unavailable. The server response was: 5.7.1 Unable to relay for dercio.tembe@oneun.org.mz
Exception details:
Message: Mailbox unavailable. The server response was: 5.7.1 Unable to relay for dercio.tembe@oneun.org.mz
Type: System.Net.Mail.SmtpFailedRecipientException
Stack trace:
 at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception)
 at System.Net.Mail.SmtpClient.Send(MailMessage message)
 at Microsoft.Exchange.Tools.ExRca.Tests.SmtpMessageTest.PerformTestReally()

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