Need SMTP port 25 opened on Virtual Machine

Question

Need SMTP port 25 opened on Virtual Machine

Michael Everett 0

We have two Azure Subscriptions. One for production and the other is for our test environment. In January 2021 we requested SMTP port 25 to be opened on our production virtual machine as our web application relies heavily on sending emails. The SR number for this was 121010726000259. It was granted by Microsoft.

We are now moving our test environment from on prem to Azure. I need to get SMTP port 25 opened on a virtual machine that is running in the test environment as the VM web application needs to replicate whats on production. My subscriptionID for the test environment is 822e1767-5100-4516-9aa7-decf773c3408. The virual machines name = prm-staging.

Praveen Bandaru 7,810 Reputation points Microsoft External Staff Moderator

2025-08-27T03:06:24.7566667+00:00
Hello Michael Everett

I understand you're looking to have SMTP port 25 opened for your virtual machine in the Azure test environment. Please note that Azure blocks outbound SMTP connections on TCP port 25 by default for most subscriptions, including Enterprise Dev/Test, as a security precaution.

If you require access to SMTP port 25, you'll need an enterprise subscription. This port is not blocked for Enterprise Agreement (EA) or Microsoft Customer Agreement for Enterprise (MCA-E) subscriptions, though external domains may still be filtered.

Go to the Virtual Network resource linked to your VM (prm-staging).

Open the "Diagnose and Solve Problems" section.

Select “Cannot send email (SMTP-Port 25)”.

Once the block is removed, you'll need to stop and restart your virtual machine to apply the new network policy.

Although enabling port 25 is an option, it's generally better to use authenticated SMTP relay services for improved reliability and IP reputation. Services such as SendGrid or Azure Communication Services are recommended and usually operate over TCP port 587, which is already open for connections.

Hope the above answer helps! Please let us know do you have any further queries.

Please do consider to “up-vote” wherever the information provided helps you, this can be beneficial to other community members.
Michael Everett 0 Reputation points

2025-08-27T03:21:58.65+00:00

Yes I understand that If you require access to SMTP port 25, you'll need an enterprise subscription but Microsoft made an exception for us previously. Please see The SR number 121010726000259 where an exception was granted for us. We need our test environment to replicate our production environment. We are only asking for one virtual machine to be allowed to send email on port 25.
Praveen Bandaru 7,810 Reputation points Microsoft External Staff Moderator

2025-08-27T10:30:26.88+00:00

Hello Michael Everett

Thank you for your response. I have initiated a private message. Please check and provide the required information for further investigation of the issue.
Praveen Bandaru 7,810 Reputation points Microsoft External Staff Moderator

2025-08-28T09:46:06.8333333+00:00

Hello Michael Everett

I checked internally and they confirmed starting November 15th, 2017, sending outbound email directly to external domains (such as outlook.com, gmail.com) from a Virtual machine (VM) was made available only to certain subscription types. Outbound SMTP connections using TCP port 25 (primarily used for unauthenticated e-mail delivery) is blocked for most new subscriptions.

In March 2022, the policy was further changed so that we will no longer allow exceptions to the block on outbound port 25 (SMTP) for Pay as you go or CSP subscription types. Existing customers and subscriptions with existing exceptions will continue to be allowed so we will not break existing customers. However, no new exemptions will be granted for these subscription types.

Even if you have a subscription with an existing exemption and need a new subscription exempted, this cannot be done due to our policy outlined publicly. You can continue to deploy new resources in your existing subscription that has already been exempted.

The only subscription type that can be exempted is Enterprise Agreement MSDN.

Hope the above answer helps! Please let us know do you have any further queries.

Please do consider to “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

Your answer

Praveen Bandaru 7,810 Reputation points Microsoft External Staff Moderator

2025-08-27T03:06:24.7566667+00:00

Hello Michael Everett

I understand you're looking to have SMTP port 25 opened for your virtual machine in the Azure test environment. Please note that Azure blocks outbound SMTP connections on TCP port 25 by default for most subscriptions, including Enterprise Dev/Test, as a security precaution.

If you require access to SMTP port 25, you'll need an enterprise subscription. This port is not blocked for Enterprise Agreement (EA) or Microsoft Customer Agreement for Enterprise (MCA-E) subscriptions, though external domains may still be filtered.

Go to the Virtual Network resource linked to your VM (prm-staging).

Open the "Diagnose and Solve Problems" section.

Select “Cannot send email (SMTP-Port 25)”.

Once the block is removed, you'll need to stop and restart your virtual machine to apply the new network policy.

Although enabling port 25 is an option, it's generally better to use authenticated SMTP relay services for improved reliability and IP reputation. Services such as SendGrid or Azure Communication Services are recommended and usually operate over TCP port 587, which is already open for connections.

Hope the above answer helps! Please let us know do you have any further queries.

Please do consider to “up-vote” wherever the information provided helps you, this can be beneficial to other community members.
Michael Everett 0 Reputation points

2025-08-27T03:21:58.65+00:00

Yes I understand that If you require access to SMTP port 25, you'll need an enterprise subscription but Microsoft made an exception for us previously. Please see The SR number 121010726000259 where an exception was granted for us. We need our test environment to replicate our production environment. We are only asking for one virtual machine to be allowed to send email on port 25.
Praveen Bandaru 7,810 Reputation points Microsoft External Staff Moderator

2025-08-27T10:30:26.88+00:00

Hello Michael Everett

Thank you for your response. I have initiated a private message. Please check and provide the required information for further investigation of the issue.
Praveen Bandaru 7,810 Reputation points Microsoft External Staff Moderator

2025-08-28T09:46:06.8333333+00:00

Hello Michael Everett

I checked internally and they confirmed starting November 15th, 2017, sending outbound email directly to external domains (such as outlook.com, gmail.com) from a Virtual machine (VM) was made available only to certain subscription types. Outbound SMTP connections using TCP port 25 (primarily used for unauthenticated e-mail delivery) is blocked for most new subscriptions.

In March 2022, the policy was further changed so that we will no longer allow exceptions to the block on outbound port 25 (SMTP) for Pay as you go or CSP subscription types. Existing customers and subscriptions with existing exceptions will continue to be allowed so we will not break existing customers. However, no new exemptions will be granted for these subscription types.

Even if you have a subscription with an existing exemption and need a new subscription exempted, this cannot be done due to our policy outlined publicly. You can continue to deploy new resources in your existing subscription that has already been exempted.

The only subscription type that can be exempted is Enterprise Agreement MSDN.

Hope the above answer helps! Please let us know do you have any further queries.

Please do consider to “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

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Need SMTP port 25 opened on Virtual Machine

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