Virtual machine SMTP (25) port blocked fix?

Question

After hacking my way through the docs to realize that port 25 is blocked I found the:

It's possible to have this block removed. To request to have the block removed, go to the Cannot send email (SMTP-Port 25) section of the Diagnose and Solve section in the Azure Virtual Network resource in the Azure portal and run the diagnostic. This process exempts the qualified enterprise dev/test subscriptions automatically. https://learn.microsoft.com/en-us/azure/virtual-network/troubleshoot-outbound-smtp-connectivity

But when I try and unblock it by following the advice there's no solution.

What is the solution so I can send emails using postfix from my server?

Answer 1

Hi @app

Port 25 is only eligible for Enterprise Agreement subscriptions. Check if your Azure subscription type is eligible for the port 25 unblock request.

You can use alternate ports or email services:

If unblocking port 25 is not feasible, consider configuring Postfix to use alternative ports that are commonly allowed for email transmission, such as port 587 (sending) or 465 (SMTPS).

Another alternative is to use a third-party email service provider, such as SendGrid, Mailchimp,which are designed to handle email delivery and often offer a free tier of service.

Get in touch if you need more help with this issue.

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