Question

How to change rDNS record

Hi, I’ve setup my own mail server and need to change the rDNS pointer to proper configure it. Can you please help? Many thanks.


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alexdo
Site Moderator
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August 6, 2022

Hi @kartone<

Changing PTR

DigitalOcean automatically configures the reverse DNS entry (PTR) on their end. It will be the hostname you choose when you set up your droplet. You can change/check this in the control panel by selecting your droplet, then settings, then renaming. As it says, changing the name there will update the PTR but not the hostname of the system, that is something you will need to do, instructions for that vary depending on the system you have installed.

To set one, you need to enter your Droplet via SSH and:

Change the hostname using hostnamectl

The first step once you have entered the droplet would be to use the hostnamectl command. Let’s say we want to name our droplet ‘ExampleName’. To do so, we need to execute the command like so

sudo hostnamectl set-hostname ExampleName

The hostnamectl command does not produce output. On success, 0 is returned, a non-zero failure code otherwise.

Update the /etc/hosts file

Next on our list would be to update the hosts file located in the etc folder. You can use any editor you want from nano, vi, vim.

sudo vim /etc/hosts

In there you’ll see something similar to

# Your system has configured 'manage_etc_hosts' as True.
# As a result, if you wish for changes to this file to persist
# then you will need to either
# a.) make changes to the master file in /etc/cloud/templates/hosts.debian.tmpl
# b.) change or remove the value of 'manage_etc_hosts' in
#     /etc/cloud/cloud.cfg or cloud-config from user-data
#
127.0.1.1 PreviousNameHere
127.0.0.1 localhost

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

Change the line which says the following

127.0.1.1 PreviousNameHere

to be

127.0.1.1 ExampleName

Save the file and exit.

Hope that this helps!

KFSys
Site Moderator
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August 5, 2022

Hi @kartone,

You can see the following docs on how to change your PTR:

https://docs.digitalocean.com/products/networking/dns/how-to/manage-records/#ptr-rdns-records

DigitalOcean automatically create PTR records for Droplets based on the name you give that Droplet in the control panel. The name must be a valid FQDN, so using example.com as the Droplet name will create a PTR record, but ubuntu-s-4vcpu-8gb-fra1-01 or my-droplet will not. Droplets with IPv6 enabled will only have PTR records enabled for the first IPv6 address assigned to it, not to all 16 addresses available.

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