Page tree

Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

Toc no bullet

Overview

Reverse DNS uses pointer records (PTR) to convert IP addresses to domain names. Forward DNS uses A records to convert domain names to IP addresses.

Configure reverse DNS


Section


Column
width72px


Column

System requirements

PTR records require authoritative DNS nameservers before they can function properly.

To find the authoritative DNS nameservers of your server's main IP address, trace the Start Of Authority (SOA). To do this, run the appropriate command:

Code Block
languagetext
dig +nssearch 0.168.192.in-addr.arpa


Note
titleNote:

In this example, 0.168.192.in-addr.arpa represents your server's main IP address.


Warning
titleImportant:
  • Changes to your server's DNS nameservers do not take effect if your server's DNS nameservers are not authoritative for your IP address. Many hosting providers do not delegate authority for PTR records to their customers.
  • Contact your upstream provider to either delegate authority to your nameservers or set up PTR records for your nameservers.
  • WHM's Add a DNS Zone interface (WHM >> Home >> DNS Functions >> Add a DNS Zone) does not currently support IPv6.



 


 

Section


Column
width72px


Column

Add the reverse DNS zone.

Navigate to WHM's Add a DNS Zone interface (WHM >> Home >> DNS Functions >> Add a DNS Zone) and enter the following information:

  • Enter your server's IP address in the Ipv4 Address text box.
  • Enter reverse DNS zone's name in the Domain text box.

    • To create a reverse DNS zone name for an IPv4 address, perform the following steps:

      1. Drop the last octet from the IP address.
      2. Reverse the order of the octets that remain.
      3. Append in-addr.arpa to the end of the octets.
  • A complete reverse DNS zone name for an IPv4 address will resemble the following example:

    Code Block
    languagetext
    128/24.0.168.192.in-addr.arpa


    Note
    titleNote:

    If your hosting provider delegates you a byte boundary that is greater than 25, separate the network range and byte boundary with a dash (), rather than a forward slash (/). For example:

    Code Block
    languagetext
    128-25.0.168.192.in-addr.arpa

    For more information, read the RFC 2317 documentation.



Column

The Domain Selection section of WHM's Add DNS Zone interface.


 


 

Section


Column
width72px


Column

Edit the reverse DNS zone file.

After you create your zone file, create each PTR record in WHM's Edit DNS Zone interface (WHM >> Home >> DNS Functions >> Edit DNS Zone).

Note
titleNote:

Your zone file already contains an NS entry for each of your server's authoritative nameservers.

  • Enter the octets 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 in the IP address.


Column

Create a PTR record in the Edit DNS Zone interface.


 


 

Section


Column
width72px


Column

Test your records.

After your domain's DNS information propagates, confirm that you properly configured reverse DNS.

To confirm that you properly configured reverse DNS, run the following command:

Code Block
languagetext
host 192.168.0.1

If you correctly configured reverse DNS, the output will resemble the following example:

Code Block
languagetext
1.0.168.192.in-addr.arpa domain name pointer www.example.com.




 


Additional documentation

Localtab Group


Localtab
activetrue
titleSuggested documentation

Content by Label
showLabelsfalse
max5
showSpacefalse
cqllabel in ("dns","nameservers","ip","ipv6") and space = currentSpace()


Localtab
titleFor cPanel users

Content by Label
showLabelsfalse
max5
showSpacefalse
cqllabel in ("dns","nameservers","ip","ipv6") and label = "cpanel" and space in ("DOC",currentSpace())


Localtab
titleFor WHM users

Content by Label
showLabelsfalse
max5
showSpacefalse
cqllabel in ("dns","nameservers","ip","ipv6") and label = "whm" and space in (currentSpace(),"DOC")


Localtab
titleFor developers

Content by Label
showLabelsfalse
max5
showSpacefalse
cqllabel in ("dns","nameservers","ip","ipv6") and space = "DD"