I need help with a PTR record

Prometheus Systems 0

I've put a small mail server on the Azure free tier to experiment with the Azure cloud services.

How do I setup a PTR record :

http://242.5.219.4.in-addr.arpa <===> http://mail.prometheus-systems.co.za

Tianyi Chang (Shanghai Wicresoft Co Ltd) 410 Reputation points Microsoft Vendor

2025-02-27T02:03:20.9033333+00:00

Hi @Prometheus Systems ,

Welcome to the Microsoft Q&A platform!

According to your description, this issue is more related to Azure DNS configuration, so I changed the tag to Azure.
Thank you for your understanding, and I hope your problem can be solved soon!
Prometheus Systems 0 Reputation points

2025-02-27T12:06:51.9066667+00:00

Figured it out.

Open the Azure CLI

Switch to Bash mode

az network public-ip update --ids $(az network public-ip list --query "[?ipAddress=='<PUBLIC IP ADDRESS>'].id" --output tsv) --reverse-fqdn "<HOSTNAME>"
Sai Prasanna Sinde 4,170 Reputation points Microsoft Vendor

2025-02-27T12:14:37.9366667+00:00
Hi @Prometheus Systems

Welcome to the Microsoft Q&A Platform! Thank you for asking your question here.

Azure controls the reverse DNS for its IP addresses, you cannot directly create or modify PTR records within your Azure DNS zone for Azure-assigned public IP addresses. Please refer the document.

To set up a PTR record, you need a static public IP address assigned to your Azure VM. This is not included in the free tier and will incur costs.

You must have a Public IP Address resource associated with your Azure virtual machine and

Before setting the PTR record, make sure your Public IP address has a DNS name label configured. This is a prerequisite for setting up a reverse FQDN.

You can use either Azure PowerShell or Azure CLI to configure the PTR record: Connect to your Azure account using the Connect-AzAccount command and get the public IP address details by following the below PS command:

$pip = Get-AzPublicIpAddress -Name "YourPublicIPName" -ResourceGroupName "YourResourceGroupName"

Next set the ReverseFqdn property of the Public IP address to your desired domain name (mail.prometheus-systems.co.za)

$pip.DnsSettings.ReverseFqdn = "mail.prometheus-systems.co.za"

Next update the Public IP address configuration with the new ReverseFqdn setting using the Set-AzPublicIpAddress command.

Set-AzPublicIpAddress -PublicIpAddress $pip

For more details, please go through this document.

Similar thread for Additional reference: https://learn.microsoft.com/en-us/answers/questions/564126/how-to-create-a-ptr-record

If you have any other questions or are still running into more issues, please let us know in the comments below.
Prometheus Systems 0 Reputation points

2025-02-27T12:43:34.6733333+00:00

No wait that doesnt seem to have worked

az network public-ip show --ids $(az network public-ip list --query "[?ipAddress=='4.219.5.242'].id" --output tsv) --query "reverseFqdn" --output tsv

Comes back blank

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I need help with a PTR record

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