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Help:Email in Cloud VPS

From Wikitech

This page contains information on best practices for managing email in Cloud VPS.

We use the word email here as a way to refer to the several protocols involved in modern and secure email exchange (smtp, spf, dkim, dmarc, pop, imap, etc).

There are some considerations you need to take into account when planning to use these emails protocols inside Cloud VPS.

Best practices

A collection of best practices.

Using Cloud VPS SMTP servers

All Cloud VPS VMs have a mail relay running, so in most cases you can set the SMTP host to localhost and port to 25. Those are set to relay mail via mx-out-a.wmcloud.org and mx-out-b.wmcloud.org.

All outbound mail from Cloud VPS must be either sent via the Cloud VPS SMTP relays or from an instance with a public floating IP address allocated. In other words, the network edge will reject outbound mail sent from private IPv4 addresses instead of applying the usual source NAT.

Sending emails from a Cloud VPS domain

If you send emails from a software running inside Cloud VPS, and you configure the software the use From: address that belongs to a Cloud VPS domain (such as wmflabs.org or wmcloud.org), make sure you are using the appropriate relay smtp server (see section above).

Not using our smtp relay servers when using a *@wmcloud.org or *@wmflabs.org sender address can result in SPF errors in the destination smtp server refusing your emails. Gmail for example will reject all inbound messages that fail SPF verification.

Sending emails from a non-Cloud VPS domain

If you need to send emails from a software running inside Cloud VPS, and you need a From: address that does not belongs to a Cloud VPS domain (such as wmcloud.org) so people reading the email replies to a different address, this is our recommendation.

  • Use a From: address from a Cloud VPS domain, such as noreply@wmcloud.org. Include a Reply-to: address in your desired external domain.
  • Use CloudVPS smtp servers as relay.

Example: 

TODO: write an example email

See also

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