Custom Domains with FastMail

• About domains
• How to set up a domain
• Mirrored domains

About domains

A custom domain allows you to receive email at a domain of your choosing (such as @greatproduct.com), not just from FastMail's many domains.

You can host the email for your domains with FastMail, providing you have a Standard or Professional account. Our account limits page lists how many domains and aliases each account type may have.

Note: FastMail does not sell domains. You'll need to purchase a domain from a domain registrar. A registrar is a company that manages the purchase and ownership of internet domain names. If you're looking for a registrar, we recommend Gandi.

Only administrators for an account can manage their custom domains.

Users on our Basic plan must remain in one of the FastMail domains.

How to set up a domain

There are three different ways you can use FastMail with your custom domain.

Nameservers hosted with FastMail

• This is the easiest, most commonly used option.
• Host your custom domain with us: we will automatically configure your domain for email support, calendar syncing, contacts syncing and other security best practices (DKIM, SPF and more).
• You will be able to manage your domain with our simple, easy to use UI. You can modify your domain records to allow for a website or other services being hosted elsewhere.
• We can detect many common configuration errors and will alert you to misconfigurations; keeping your online presence active.
• Step by step instructions on adding your domain to FastMail with NS/MX

Nameservers hosted elsewhere, but MX records pointing to FastMail

• For users whose domain is already hosted elsewhere (and have no ability or desire to change nameserver host), but who would like to use FastMail for mail hosting.
• Configuration requires manual intervention at the nameserver host in order to configure the correct values to ensure mail is properly delivered to FastMail. We provide you the values you'll need to enter with your hosting provider.
• FastMail can detect some MX-related configuration errors and will alert you to misconfigurations.
• Step by step instructions on adding your domain to FastMail with MX-only

No NS/MX at FastMail, but mail redirected to FastMail

• In rare cases, FastMail isn't hosting the nameserver or the mail exchange records, but mail is still being redirected to FastMail.
• Use this option if you're using a third party filtering service to process mail before it is sent to us.
• FastMail's own spam filtering will be much less effective if you use this option.
• We provide all the values you'll need to configure on your current MX server to ensure correct mail delivery. FastMail is unable to detect misconfigurations in this case, as all the domain management is held elsewhere.
• Step by step instructions on adding your domain to FastMail with no NS/MX

Mirrored domains

With email, it's easy to have multiple domains that "mirror" each other. So you might have example.com and example.com.au, and you want any email address at example.com to work at example.com.au as well. To set this up:

1. Pick a "primary" domain (say example.com), and create all your domain aliases and accounts in that domain.
2. Create a single alias in your alternate domain with the special * (star) value (e.g. *@example.com.au) and set the target of that alias to *@example.com. Then any valid email address at example.com, will also work at example.com.au. Note that this only works for email addresses; for websites, you have to explicitly create the website for each domain, or set up a redirect to the primary domain.