"DNS Record not found"

[wm20472]

IP: 115.160.128.100
I have set 100.128.160.115.in-addr.arpa in Directadmin > DNS Administraton
I testing my IP in mxtoolbox.com Reverse Lookup, it find "DNS Record not found"
How can I solve?

 

[wm20472]

I use http://www.aboutmyip.com/AboutMyXApp/Quicktest?domainName=provisionhk.com

result:
Reverse IP Lookup: WARNING - Reverse IP lookup test failed on your server. Some servers on the Internet may reject emails from this server.

 

[Active8]

You have to do this at your provider , PTR or Reverse IP setup is mostly done at your server provider, check his control panel for your server / vps