Email forwarding

You can set up a rule to forward all of your mail from Fastmail to another email inbox by following these steps:

  1. Open the Settings → Mail rules screen and click Create rule.
  2. For the condition, choose the All messages option and click Continue.
  3. Select the Send a copy to action and enter in the email address you would like to forward mail to.
  4. Click Save to save the rule.

You can also create specific conditions for these rules so that messages will only be forwarded if they follow certain patterns.

Note that a forwarding rule will not apply to any message caught by discard rules, or any message filtered as spam.

Specific address forwarding

If you just want to forward all mail sent to one of your addresses, you can do this by directly setting the target of that specific address to the address you wish to forward to.

The main differences between this approach and using a rule are:

  • The address forwarding is only possible on that specific address, not email sent to your main address. If you want to forward email sent to your main address, you have to use the Settings → Mail rules screen.
  • The address forwarding will apply to all messages sent to that specific address. There's no way to only forward emails that only meet a particular criteria.
  • Forwarding emails through specific addresses will mean that spam protection is not run before these messages are sent out. If you would like the messages to be run through Fastmail's spam filter first, forward them by creating a Rule.

If these limitations on virus, backscatter, and spam filtering are OK, then you can use the Settings → My email addresses screen to target specific addresses at the external address(es).

Known issues with email forwarding

While forwarding is an easy way to send a copy of the email you received to a different address, forwarded emails may not always be successfully delivered, for a few reasons.

Forwarding breaks SPF

SPF (Sender Policy Framework) lets the recipient check that the system that sent the email for a particular domain is authorized to do so. SPF is a standard followed by most reliable email services, as it helps to prevent spoofing and protects email services' reputation for reliable mail delivery.

Unfortunately, SPF breaks when emails are forwarded. As an example, if someone sends from to Fastmail, and the Fastmail account is set to forward all messages to Gmail, the SPF check for the forwarded message will fail, because Fastmail is not allowed to deliver mail for addresses.

DKIM signing the emails can help reduce these issues.

Recent shift to stricter SPF policies

We’ve noticed that various email providers have increased the strictness of authentication checks recently. For example, Gmail has started to bounce emails that fail SPF checks, even if it’s a soft fail when the email is not DKIM signed. This means that you may see an increase in issues with forwarded emails.

We are working with other email providers (including Gmail) to mitigate the issue, but there are a few things you can do to prevent the issue:

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