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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.

Records of operations with the email service are saved in audit logs.

How it works

The service works as an MTA (mail transfer agent) and forwards mail from your servers to external networks. Information is transmitted in a secure form via the TLS protocol; the service does not process email data or store it. SMTP (Simple Mail Transfer Protocol) is used for sending.

When connecting the service, a mail resource is created for you, to which you add your domain. You can add up to three domains to a resource. For domains within one resource, the same login and password will be used for connecting to the SMTP server and common statistics will be collected.

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 sending via SMTP. At the mail node, the list of recipients is verified — addresses that are in stop lists are excluded. After that, the mail is sent to the remaining recipients.

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

  • Return-Path — contains the technical email sender@servercore-smtp.com, to which delivery status messages are sent. If you need to specify your own email in this field, create a ticket;
  • DKIM-Signature — confirms that the email service has the right to send mail on behalf of the domain and protects against being marked as spam.

Pay attention to potential errors in the SMTP dialogue.

Limitations

The service has the following limits for a mail resource:

  • no more than one resource per project;
  • no more than three domains per resource;
  • sending speed through a resource is 100 emails per five minutes, regardless of the number of domains in the resource.

If you need to create more than one mail resource in a project, add more than three domains to a resource, or increase the sending speed, create a ticket and describe the purpose of your mailings. We will review the possibility of increasing the limits.

Only UTF-8 encoding is supported for emails.

There are no limits on the number of mailing recipients, email size, or number of attachments in the service.

We recommend:

  • limiting email size to 10 MB or less. Recipient mail services may reject emails with larger sizes as suspicious;
  • specifying no more than five recipients in a single email. If at least one of the recipients is in a stop list, the email will not be sent to any of them.