reverse DNS lookup failed

[news.microsoft.com]

Hello everyone.



I do not know that what is happening in my mail server, usually have
Able to send mails to a German domain until yesterday when it started to
Notify the server to send an NDR when that domain German.



I hope you can help me with this problem.


Unable to locate the following recipients:



Name, Name 22/01/2008 15:08

No permission to send to this recipient. Please
Contact your system administrator for assistance.

<Server.domain.pt # 5.7.1 SMTP; 550 5.7.1 This system is
Configured to reject mail from XXX.XXX.XX.XXX (reverse DNS lookup failed)>

[John Oliver, Jr. [MVP]]

Do you have a Reverse PTR Record for your IP?

http://www.intermedia.net/support/kb/default.asp?id=1317

In addition, do you relay your mail through a Smarthost such as your ISP?
--
John Oliver, Jr
MCSE, MCT, CCNA
Exchange MVP 2008
Microsoft Certified Partner

Post by news.microsoft.com
Hello everyone.
I do not know that what is happening in my mail server, usually have Able
to send mails to a German domain until yesterday when it started to Notify
the server to send an NDR when that domain German.
I hope you can help me with this problem.
Name, Name 22/01/2008 15:08
No permission to send to this recipient. Please Contact your
system administrator for assistance.
<Server.domain.pt # 5.7.1 SMTP; 550 5.7.1 This system is
Configured to reject mail from XXX.XXX.XX.XXX (reverse DNS lookup failed)>