Hello All......My domain is listed in the blacklisted domains.  Following is the message.

RATS-Dyna - Probable PC or home connection infected with a Trojan, Bot, or Emailer Program -- If you are listed in the Spamrats / RATS-Dyna blacklist and you operate your own mail-server, you likely have no valid PTR-Record. If you are simply a home email user, you have a dynamic IP Address and may need to contact your ISP for assistance. If you operate a domain name and are using your ISP for SMTP-Authentication, try contacting your DNS Provider to use their SMTP-Services instead.

I am only guessing that I need to create PTR Record for my domain which BTW does not exist.  I would appreciate if someone could guide me as to how I can create this in my external domain by example like IP Part and Name Part. 

Thanks in advance. 

Hi Junkie,

Thank you for your question.

We could type the domain in the following link check if the domain is in blacklist, then it will direct you to someone by the correct way.

http://mxtoolbox.com/blacklists.aspx

Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please make sure that you completely understand the risk before retrieving any suggestions from the above link.

In addition, we didnt create PTR record for external domain in the organization. If we want to create PTR record in external DNS, we could contact the ISP to solve it.

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim

Thanks for the reply.

What would happen if there are two PTR records for the same IP Address?  One correct one and another that is there by default?

Hi Junkie,

PTR record resolve email address to IP, so we did not use the different domain name point to the same IP address.

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim

You don't create the PTR for your IP address or domain.
Your ISP does that.

If you are on a home connection, then you will probably be unable to get a PTR configured.

All that you can do is configure an A record which matches the PTR that you are going to ask the ISP to set.

It is impossible to have two PTR on the same IP address. While Windows DNS will allow you to do it, on the internet that is an invalid configuration and most ISPs will not allow it. If you ask for one to be set, it will overwrite the other.

Simon.

Thanks for the reply.

Yes, ISP creates it and they have and change is already working.