Create and Manage Reverse DNS Record

A reverse DNS (rDNS) maps a public IP address and a domain name. A reverse DNS lookup zone contains the attributes that instruct Cloud DNS to perform a Pointer (PTR) lookup against DNS servers to find the domain name mapped to the IPv4 or IPv6 addresses.

For more information about IPv6 configuration in the DCD, see IPv6 Configuration.

Note:

• Reverse DNS lookup is supported only for the following:

  • Public IPv6 addresses assigned to your VDCs.

  • Reserved IPv4 addresses.

• The IPv4 address must be from a reserved IP range. To reserve an IPv4 address, follow these steps:

  • In the DCD go to the Menu > Network > IP Management.

  • Enter a name and the number of IPv4 addresses.

  • Select a region where you want your IPv4 addresses to be reserved.

  • Select Reserve IP to reserve the IPv4 address.

  • Select OK to confirm the reservation.

• For a reverse DNS record, you can use an IPv6 address that belongs to any of the /56 IPv6 blocks assigned to the VDC and has a prefix length of /128. For example, consider the IPv6 address 2001:db8:1234:5678::1/128, which belongs to a 2001:db8:1234:5678::/56 block. For more information, see IPv6 Configuration.

Prerequisites

• You need an IONOS Cloud account with API credentials configured with the appropriate permissions.

• You must be a contract administrator, owner, or a user with Access and manage DNS privilege to create and manage PTR records. You can also set User privileges via the API.

• Before creating a Reverse DNS record, it is recommended to create an A or AAAA record for the IP address you want to use for the reverse DNS record. For more information, see Create a DNS Record.

• Sub-users can create Reverse DNS records for IPv4 addresses only if the user group they belong to has access to the concerned reserved IP block. For more information, see Add users to a group.

Create a PTR Record for Reverse DNS

To create a PTR record for a reverse DNS, follow these steps:

1. In the DCD, go to Menu > Network > Cloud DNS.

Select Cloud DNS from the menu

2. Select the Reverse DNS tab and click Create PTR Record to create records.

Create a PTR record

3. Enter the following details in the Create PTR record window:

   • IP Version: Choose either IPv4 or IPv6 address based on the need.

   • IP Address:

     • If you have chosen an IPv4 version, your reserved IPv4 addresses will appear in the drop-down list. Select an IPv4 address from the reserved list of addresses.

   

   Create a PTR record with an IPv4 address

   • For an IPv6 version, specify an IPv6 address and ensure that it belongs to any of the /56 IPv6 blocks assigned to the VDC and has a prefix length of /128.

   

   Create a PTR record with an IPv6 address

   • Name: Enter a name or a sub-domain that must be mapped to the IP address.

   • Description (Optional): Enter an appropriate description for your reverse DNS zone.

4. Click Create PTR Record to create the PTR record.

Define PTR record properties

Result: Your PTR record creation is successful.

View PTR Records

To view a list of PTR records, do the following:

1. In the DCD, go to Menu > Network > Cloud DNS > Reverse DNS tab.

List of PTR records

Result: A list of all PTR records with the following details are displayed: — IP ADDRESS: Displays the IP address of the respective PTR record. — NAME: Displays the name of the mapped domain or subdomain. — CREATED DATE: Indicates the date of PTR record creation. — ACTIONS: Select the three dots to perform the following operations:  — Details & edit: Select to view the details of the respective PTR record or update it, if necessary.  — Copy UUID: Copy the UUID of the PTR record.  — Copy HREF: Copy the Cloud DNS API HREF of the PTR record.  — Delete: Select the option to delete the respective PTR record, and in the Delete PTR record? confirmation dialog box, click Delete to confirm deletion. For more information, see Delete a PTR record.

Update PTR Record details

You can update the domain or sub-domain name associated with the PTR record or the description of the PTR record. Follow these steps to update a PTR record:

1. In the DCD, go to Menu > Network > Cloud DNS > Reverse DNS tab.

2. You can follow either of these options to update a record:

   • Select the corresponding IP address from the IP ADDRESS column.

   • Select Details & edit from the drop-down list in the ACTIONS column.

3. Modify the Name and Description, if necessary.

4. Select Update PTR record to save the changes.

Info: You can click Delete to delete the respective PTR record. For more information, see Delete a PTR record.

Update a PTR record

Delete a PTR record

To delete a PTR record, follow these steps:

1. In the DCD, go to Menu > Network > Cloud DNS > Reverse DNS tab.

2. Click Delete from the ACTIONS column to delete the corresponding PTR record.

Delete a PTR record

Alternatively, to delete a specific PTR record, you can also do the following:

1. Select the corresponding IP address from the IP ADDRESS column or select Details & edit from the drop-down list in the ACTIONS column.

2. Click Delete in the Update PTR record window.

Alternative delete option

3. Select Delete in the Delete PTR record? dialog box to confirm deletion.

Confirm deletion

Result: The selected PTR record is successfully deleted.