Reverse DNS not working

[Shayne]

(06-12-2009 11:02 PM)MasterTH Wrote:  it must be registered anywhere to give the correct answer to the mail-servers.

when the domain isn't registered anywhere the mailservers you try to send mails think that your server is an spam-sender and will reject any mails that come from you

Some mail is getting through

I am just having problems with certain people.

This box is a DNS server hosting 3 registered domains. All work fine and mail in general works from all the domains. just certain mails when being delivered to me get bounced with HELO & DNS MX settings.