Enable port 25 communication for virtual machine on Azure RRS feed

  • Question

  • Hello. 

    We have a pay-as-you-go subscription and need to send emails from a virtual machine directly to external email providers. We are aware that port 25 communication is blocked from all resources under this subscription, but we need your help to remove this restriction.

    Can you help us to solve this issue?

    Tuesday, August 7, 2018 2:37 PM


  • Yes, bydefault these ports are blocked for both new and existing customers to prevent malicious users from using Azure IP addresses for abuse and adversely affecting the reputation of all Azure IPs.

    Microsoft recommends that you utilize authenticated SMTP relay services (typically connected via TCP port 587, but often others, as well) to send email from Azure Virtual Machines. SMTP relay services specialize in sender reputation, to minimize the possibility that third-party email providers reject messages. Such SMTP relay services include, but are not limited to, Exchange Online Protection and SendGrid. Use of SMTP relay services is in no way restricted in Azure, regardless of your subscription type.

    • Pay-as-you-go: Outbound port 25 communication is blocked from all resources. If you need to send email from a virtual machine directly to external email providers (not using an authenticated SMTP relay), you can make a request to remove the restriction. Requests are reviewed and approved at Microsoft's discretion and are only granted after anti-fraud checks are performed. To make a request, open a support case with the issue type Technical, Virtual Network Connectivity, cannot send e-mail (SMTP/Port 25). 

    Suggest you to refer the below article:


    NOTE: If Azure allows you to send email over port 25, Microsoft cannot guarantee email providers will accept inbound email from your virtual machine. If a specific provider rejects mail from your virtual machine, you must work directly with the provider to resolve any message delivery or spam filtering issues or use an authenticated SMTP relay service.

    Also, would suggest you to upvote in the feedback link regarding the blocked ports.


    If this answer was helpful, click “Mark as Answer” or Up-Vote. To provide additional feedback on your forum experience, click here.

    • Proposed as answer by Nirushi J Tuesday, August 7, 2018 3:00 PM
    • Marked as answer by Muñoz085 Tuesday, August 7, 2018 3:39 PM
    Tuesday, August 7, 2018 3:00 PM