For Testing Purpose made a virtual machine and setup a Mail server. Everything form the Server Site and Access from external is working as planed. But to make i right i wantet do add a PRT record. so i created a Zone with an in addr record with the ip the vm received. I hat do errors. But when i check with mxtoolbox ptr i do not receive the record. Does anyone have any experiance with this?

@Aycholos Escher, Heinzer-it AG , Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well. I understand that you would like to add a PTR record to the Public IP of your VM. Please let me know if my observation is incorrect. For this to work, you must have a valid DNS name label configured in your PIP Configuration. See : Note : DNS name label provides A record and not PTR Once the above is done, you can proceed to configure the PTR record. There are certain conditions to define a PTR record, The DNS name for the public IP address: contosoapp1.northus.cloudapp.azure.com . The DNS name for a different PublicIpAddress in the same subscription, such as: contosoapp2.westus.cloudapp.azure.com . A vanity DNS name, such as: app1.contoso.com . As long as the name is first configured as a CNAME pointing to contosoapp1.northus.cloudapp.azure.com . The name can also be pointed to a different public IP address in the same subscription. A vanity DNS name, such as: app1.contoso.com . As long as this name is first configured as an A record pointing to the IP address 23.96.52.53. The name can also be pointed to another IP address in the same subscription. See : Validation of reverse DNS records What this states is that, (from my example) You can add the PTR record as "domainlabel.centralindia.cloudapp.azure.com" to your Public IP or any Public IP in the subscription without any additional configuration. If you want the PTR record to be a custom one, say "myapp.mycompany.com" , then the "myapp.mycompany.com" should resolve to your Public IP or any other Public IP in the subscription either via A record or CNAME record. Only then Azure will let you add "myapp.mycompany.com" as PTR record. You can find the Powershell command here . Kindly let us know if this helps or you need further assistance on this issue. Thanks, Kapil

I made a virtual Machine with an mail server. I want to add a ptr Record.

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KapilAnanth-MSFT 48,331 Reputation points Microsoft Employee

2024-04-30T07:33:56.7766667+00:00
@Aycholos Escher, Heinzer-it AG ,

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you would like to add a PTR record to the Public IP of your VM.

Please let me know if my observation is incorrect.

For this to work, you must have a valid DNS name label configured in your PIP Configuration.

See :

Note : DNS name label provides A record and not PTR

Once the above is done, you can proceed to configure the PTR record.

There are certain conditions to define a PTR record,

The DNS name for the public IP address: contosoapp1.northus.cloudapp.azure.com.

The DNS name for a different PublicIpAddress in the same subscription, such as: contosoapp2.westus.cloudapp.azure.com.

A vanity DNS name, such as: app1.contoso.com. As long as the name is first configured as a CNAME pointing to contosoapp1.northus.cloudapp.azure.com. The name can also be pointed to a different public IP address in the same subscription.

A vanity DNS name, such as: app1.contoso.com. As long as this name is first configured as an A record pointing to the IP address 23.96.52.53. The name can also be pointed to another IP address in the same subscription.

See : Validation of reverse DNS records

What this states is that, (from my example)

You can add the PTR record as "domainlabel.centralindia.cloudapp.azure.com" to your Public IP or any Public IP in the subscription without any additional configuration.

If you want the PTR record to be a custom one, say "myapp.mycompany.com" , then the "myapp.mycompany.com" should resolve to your Public IP or any other Public IP in the subscription either via A record or CNAME record.

Only then Azure will let you add "myapp.mycompany.com" as PTR record.

You can find the Powershell command here.

Kindly let us know if this helps or you need further assistance on this issue.

Thanks,

Kapil
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Aycholos Escher, Heinzer-it AG 20 Reputation points

2024-04-30T09:16:49.4033333+00:00

Thank you i think i understood what you mean. i made an Iabel let us say test.westeurope.cloudapp.azure.com. ping is working

Let Pretend my Public ip which my vm received from microsoft is 1.2.3.4

so i have my DNS entry as the following

4.3.2.1.in-addr.arpa

and i will point 1234 is this right?

KapilAnanth-MSFT 48,331 Reputation points Microsoft Employee

2024-04-30T09:33:03.93+00:00

@Aycholos Escher, Heinzer-it AG ,

Unfortunately, No.

You must understand the fact that you do not own the "4.3.2.1.in-addr.arpa" domain.

The corresponding ISP or Cloud Vendor of the IP 1.2.3.4 own and manage the domain. Only they can make such entries in the domain "4.3.2.1.in-addr.arpa".

NOTE:

Creating a Domain in Azure is not as same as owning the domain

See : Delegation of DNS zones with Azure DNS

In fact, Azure is not even a domain registrar as of now. You have to purchase a domain from a third party registrar and use Azure only for managing the domain

In our case, it is Azure who owns the domain "4.3.2.1.in-addr.arpa" as Azure issued you 1.2.3.4,

Basically, by utilizing the above PS commands, you are simply requesting the Azure platform to update the PTR record in the domain "4.3.2.1.in-addr.arpa".

When you do so, Azure checks if the "test.westeurope.cloudapp.azure.com." is resolving to 1.2.3.4

Only then will Azure add the PTR record, else it will throw an error.

Since you have already added "test.westeurope.cloudapp.azure.com." as the domain label (A record) , the powershell commands should succeed and you should not face any issues.

$pip = Get-AzPublicIpAddress -Name "<YOURPIP>" -ResourceGroupName "<YOURRG>" $pip.DnsSettings.ReverseFqdn = "test.westeurope.cloudapp.azure.com." Set-AzPublicIpAddress -PublicIpAddress $pip

Hope this adds more clarity

Cheers,

Kapil

Aycholos Escher, Heinzer-it AG 20 Reputation points

2024-04-30T17:08:47.7166667+00:00

Hi Kapil

Great champ it did work. Just wondering can i delete it too? or will it be deleted when i remove the vm?

thxs a lot

KapilAnanth-MSFT 48,331 Reputation points Microsoft Employee

2024-04-30T17:16:59.9166667+00:00

@Aycholos Escher, Heinzer-it AG ,

Yes.

If you no longer need a Reverse Fqdn, you can simply update the value as "".

See : Remove reverse DNS from an existing public IP address

In Powershell,

$pip = Get-AzPublicIpAddress -Name "<YOURPIP>" -ResourceGroupName "<YOURRG>" $pip.DnsSettings.ReverseFqdn = "" Set-AzPublicIpAddress -PublicIpAddress $pip

NOTE:

The reverse FQDN record will not be deleted with the VM.

Instead, it will be deleted with the Public IP, i.e., it is a property of the PIP and not of the VM

I have summarized our discussion and posted it as an answer.

I would highly appreciate if you could Accept the answer and close this thread

Original posters help the community find answers faster by identifying the correct answer.

Thanks,

Kapil

Aycholos Escher, Heinzer-it AG 20 Reputation points

2024-05-02T12:16:09.9666667+00:00

Great Problem was resolved. Had PTR entry.

KapilAnanth-MSFT 48,331 Reputation points Microsoft Employee

2024-05-02T12:27:03.3066667+00:00

@Aycholos Escher, Heinzer-it AG ,

Glad we could be of service.

Thanks for your continued contribution on Q&A and appreciate much for taking the time to accept the answer and share your feedback.

Cheers,

Kapil
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I made a virtual Machine with an mail server. I want to add a ptr Record.

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