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About Servercore email service

The Servercore email service is a service for secure outgoing email delivery from your servers in Servercore to external networks. You can only send email through the service from servers within the Servercore infrastructure.

How it works

The service acts as an MTA (mail transfer agent) that forwards mail from your servers to external networks. Information is transmitted securely via the TLS protocol; the service does not process email data or store it. SMTP (Simple Mail Transfer Protocol) is used for delivery.

When connecting the service, an email resource is created for you, to which you add your domain. You can add up to three domains to a resource. For all domains in a single resource, the same username and password will be used to connect to the SMTP server, and a combined statistics report will be generated.

After connecting the service, you send emails from your server to the service’s mail node (SMTP relay). You can use any utility that supports SMTP for delivery. At the mail node, the recipient list is checked — addresses that are on stop lists are excluded. After that, the mail is sent to the remaining recipients.

When sending, technical service headers are added to the emails:

  • Return-Path — contains the technical email sender@servercore-smtp.com, where delivery status notifications are sent. If you need to specify your own email in this field, create a ticket;
  • DKIM-Signature — confirms that the email service is authorized to send emails on behalf of the domain and protects it from being flagged as spam.

Please note the possible errors in the SMTP dialog.

Limitations

The service has the following limits for an email resource:

  • no more than one resource per project;
  • no more than three domains per resource;
  • sending rate via a resource — 100 emails every five minutes regardless of the number of domains in the resource.

If you need to create more than one email resource in a project, add more than three domains to a resource, or increase the sending rate, create a ticket and describe your mailing goal. We will see if we can increase the limits.

Only UTF-8 encoding is supported for emails.

The service has no limits on the number of recipients, email size, or the number of attachments.

We recommend:

  • limiting email size to no more than 10 MB. Recipient email services may reject large emails as suspicious;
  • specify no more than five recipients in a single email. If at least one recipient is on the stop list, the email will not be sent to any of them.