How to Configure Reverse DNS PTR Record

Setting up a PTR Record in your DNS is a vital step for any website, especially if you are sending emails as this is an ever growing requirement for spam checking – A Reverse DNS record allows any server to verify that the IP address is authorized with the domain name and as such tells a server receiving an email from your domain that it is authorised to do so.  

Step 1: Authoritative DNS

Note: With WebDesires we have authority to setup PTR records, please click our support link at the bottom of this article and we can assist you in setting up your PTR record.

You need to make sure your DNS nameservers have authority for your IP address, most hosting providers do not provide authority for PTR records and in such cases you will need to contact them directly to enable the feature or set-up the PTR records for you, if you are in doubt contact your hosting provider before proceeding.  

Step 2: Adding the Reverse DNS Zone

Note: For the remainder of this article we will assume that your server IP address is:

Firstl in WHM you need to navigate to DNS Functions > Add a DNS Zone.

Annex A - Enter IP and Domain Name

Annex A – Enter IP and Domain Name

You should now see a box that looks similar to “Annex A” which asks you to enter an IP and Domain. In the IP address field enter: The domain field is a little trickier, follow these steps:

  1. Drop the last octet from the IP address: >
  2. Reverse the order of the octets that remain: 108.56.3 > 3.56.108
  3. If your hosting provider delegates you PTR authority, append their network range and byte boundary, separated by a slash (/) if the first octet is 25 or below, or a dash (-) if the first octet is above 25: 128/3.56.108 -or- 128-32.56.108
  4. Append in-addr.arpa to the end of the octets: 128/3.56.108.in-addr.arpa

At step 4 you should have the domain that you need to enter into the domain field (128/3.56.108.in-addr.arpa) click save.  

Step 3 – Edit Reverse DNS zone file

After you have created your zone file in step 2 you need to create each PTR record for each domain, in WHM navigate to: Home >> DNS Functions >> Edit DNS Zone

  • Enter the octets or nibbles in an available text box under the Add New Entries Below this Line heading.
  • Select PTR in the appropriate menu. The Hostname text box will appear.
  • Enter the Hostname that corresponds to the last octet or nibble in the IP address.
Example of DNS records

Example of DNS records

Author: Dean Williams

Professional PHP Web Developer with expertise in OpenCart Web Development, WordPress Web Development, Bespoke Systems - also a seasoned Linux Server Administrator.

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