OS: SME Server 6.0.1
the server is used to Email server only, recently reports show that my IP was blocked by others.
for example;
Users at the University of Minnesota also have an option to refuse e-mail originating outside the University. Also, certain "From:" addresses are blocked. In particular, if the right-hand side of your "From:" address (the part after the "@") does not exist in the DNS, your e-mail will be rejected. Be sure to follow the URL in the bounce message to verify whether either of these are the cause of your message being blocked.
DNS : block
Description: No hostname (PTR) associated with address xxx.xxx.xxx.xxx
How to solve this problem in SME?pls thanks