![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(182.40000000000003, 51%, 27%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EU%3C/text%3E%3C/svg%3E)
Azure Virtual Network
An Azure networking service that is used to provision private networks and optionally to connect to on-premises datacenters.
Outbound SMTP connections on TCP port 25 from Azure are generally blocked to ensure security and compliance with industry standards. This means that even if you have allowed port 25 for smtp.gmail.com, Azure might still prevent the traffic from reaching that server. The Azure platform blocks outbound SMTP connections on port 25 for deployed VMs, which could be the reason why your traffic is not reaching smtp.gmail.com.
To send email from Azure, it is recommended to use authenticated SMTP relay services, typically over TCP port 587, which is not blocked. This approach helps maintain IP reputation and ensures reliable email delivery.
If your setup requires using port 25, you may need to check if your Azure subscription allows sending emails directly over that port, as this is dependent on the type of subscription you have. For example, certain subscription types may have restrictions on using port 25.
For further troubleshooting, you might want to consider using tools to test connectivity or opening a support case with Azure for assistance.