Configure Your Linode for Reverse DNS (rDNS)

Computers use DNS to determine the IP address associated with a domain name. Reverse DNS lookup does the opposite by resolving an IP address to a designated domain name. You should always set the reverse DNS, even if your Linode hosts more than one domain.

Reverse DNS uses a pointer record (PTR) to match an IP address with a domain or subdomain. PTR records are generally set with a hosting provider, so reverse DNS is set in the Linode Cloud Manager.

Before You Begin

Before setting the reverse DNS for your Linode, configure your domain zone and DNS records through Linode’s DNS Manager. See our Introduction to DNS Records and Common DNS Configurations guides for more information about PTR and DNS.

Specifically, you will need to create an A record for the domain name (or subdomain) that you want to assign your reverse DNS to. The value of this A record should be the IP address that you’re setting up reverse DNS on.

Setting Reverse DNS

1. Click on the Linodes link in the sidebar to access a list of all your Linodes.

2. Select the Linode whose reverse DNS you would like to set up and click on its Network tab.

3. Find the IP address whose reverse DNS you would like to configure and click on the Edit rDNS button, which may be available within the more options ellipsis menu on smaller screen sizes.

4. In the Edit Reverse DNS form, enter your Linode’s fully qualified domain name and click on the Save button. The default value of x.ip.linodeusercontent.com can be safely removed or replaced. Leave the field blank if you wish to remove the previously configured rDNS value without setting a new value.

   Note

   If you did not previously set up an A record for your domain that matches your Linode’s IP address, you will see an error like the following:

   We were unable to perform a lookup for 'example.com' at this time.

   You may also see this error if you very recently created your A record, as it can take some time for your DNS changes to propagate.

5. You should now see the domain name you entered listed under the Reverse DNS column.

   Note

   If you want to set up reverse DNS for both the IPv4 and IPv6 addresses, you can perform the same steps for the IPv6 address.

IPv6 Pools and Routed Ranges

While single IPv6 addresses can be configured following the same process as IPv4 addresses, reverse DNS for IPv6 pools (/116) and routed ranges (/64, /56) are configured a little differently.

1. Follow the steps for Setting Reverse DNS, clicking the Edit rDNS button next to an IPv6 pool or range (instead of an individual address).

2. In the Edit Reverse DNS form, enter the IPv6 address you’d like to use as well as the fully qualified domain name for that address. The IPv6 address needs to be a valid address within the selected IPv6 pool or range. Click on the Save button.

3. You can add or edit the rDNS values for other IPv6 addresses within that IPv6 pool or range by repeating this process. Once more than one rDNS entry is added, the Reverse DNS column of the IPv6 table will show you exactly how many IP addresses have been given rDNS entries.

4. To see each rDNS entry in more detail, click on the addresses entry in the rDNS column for your IPv6 pool or range. A new window will appear listing the IPv6 addresses you’ve configured along with their associated domain names.