Migrating business email to Fastmail

If you have a custom domain for your business, you can use it with Fastmail and set up all the accounts and additional addresses you require. Transitioning onto Fastmail is painless and can involve no downtime.

This guide is intended for admins of multi-user accounts.

Initial mail setup

First, you will need to set up your Fastmail account by following these steps:

  1. Add your domain to Fastmail, but keep the MX registration pointing at your old host.
  2. Create your users in Fastmail.
  3. Add any additional email addresses to Fastmail.

At this point in the setup, all your mail is still being delivered to your old provider, but you have the users ready on Fastmail. From here, you can choose to either migrate everyone all at once, or slowly migrate one user at a time.

Migrate users and domain

If you only have a few users, or you are able to complete the migration out of core business hours, then migrating all at once is an easier option.

If you have many users, or you wish to avoid any downtime, then you may prefer to migrate one user at a time instead.

Option 1: Migrate all at once

Switch your MX records to point to Fastmail. After about an hour, new mail should be delivered to Fastmail and into your users' inboxes.

You can then use our email import tool for each user to pull their old messages from the other provider into their new Fastmail account.

Note: If they have mail on their desktop downloaded via POP, they'll need to manually transfer those folders to Fastmail's servers if they want this mail to be backed up.

Pros: Less steps to complete migration.

Cons: After your MX records have been changed to point to us, mail will still arrive at the old provider for a short period of time (likely about an hour or so). Users will also need to wait for their import to finish before they will be able to see emails in their Fastmail inbox. The amount of time it takes for the import to finish can be lessened if the migration takes place out of regular business hours.

Option 2: Migrate one at a time

At your existing email provider, set the user's email account to forward all email to us via one of our forwarding tunnel addresses. This will ensure that any new email that arrives at your old provider will be forwarded to Fastmail.

Use the email import tool to copy email for that user from your old provider to the user's new Fastmail account. If they have mail on their desktop (downloaded via POP), they'll need to manually transfer those folders to Fastmail's servers if they want it to be backed up.

At this point, this user can use Fastmail to send and receive their email, even though your old provider is still active. When all users have been migrated this way, then you can switch your MX records to point to us.

Pros: User experiences no delay: they have complete access to their old mail and new from Fastmail once the mail import is completed. You can check the status of each user individually.

Cons: An extra step is required in setting up the forwarding tunnels for each user. This can be time consuming if there are many users, but fortunately they don't have to be all done at once.

Migrate contacts and calendar

Each user will want to also migrate their contacts and any calendar entries. Follow our personal migration guide on completing these steps. It also covers how to change settings on email clients and mobile devices, and how to use two-step verification (2FA) to keep accounts secure.

Forwarding tunnel

The forwarding tunnel lets you forward email from an existing service to an account with the same name at Fastmail. For example, if you have the account john@yourdomain.com at an existing service, you can create an account with the same name at Fastmail then use one of our forwarding addresses to deliver mail to it, even though the MX records for your domain still point to your previous email host.

There are two encoding options you can use, because some providers are limited as to what characters and/or the domain length you can put in an email address to forward to. To forward email to the Fastmail account john@yourdomain.com, you can use either of:

  • john@yourdomain.com.forward.messagingengine.com
  • john#yourdomain.com@forward.messagingengine.com

Please note that this only works when forwarding to your main username. It doesn't work for other addresses you have at Fastmail. Also be aware that if you change the main username, we automatically save the old username as one of your additional addresses. This lets emails sent to the old address be received, but doesn't work for emails sent to the old forwarding tunnel address.

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