In rare cases, Fastmail isn't hosting the nameservers or MX records for a domain, but mail is still being redirected to Fastmail to host, e.g. if you're using a third party filtering service to process mail before it is sent to us.
On this help page, we'll provide the values you will need to set up your DNS with your domain registrar to make sure mail is delivered correctly. We won't be able to identify any setup errors, as the domain management is held elsewhere.
There are three general steps involved:
Additional information:
1. Add your domain
You will first need to add your domain in Fastmail using the domain setup wizard on the Settings → Domains screen.
Click the Add or buy domain button, then choose the Use a domain you already own option. This will bring up the domain wizard. Type your domain into the box. We will detect whether your domain has been registered or not. It's important that the domain has already been registered by you at a domain registrar; otherwise you won't be able to make the necessary changes.
Follow the on-screen prompts. At the end, we will offer instructions for changing your DNS records. Since you won't be changing these records, scroll to the bottom and click Close and check it later.
Fastmail will report the domain as Inactive. Since your domain isn't hosted with Fastmail and the DNS records do not point to Fastmail, this warning will remain.
Please note: The domain setup wizard can only set up additional addresses on legacy plans. If you are on a legacy plan, you will need to add users manually in order to create additional user accounts at your custom domain.
2. Apply DKIM and SPF records
You will need to set the DKIM and SPF records with your domain server to ensure your mail is properly signed.
- Go to the Settings → Domains screen and click Edit next to your domain.
- On the following page, click Get instructions.
- Follow the instructions onscreen for adding DKIM and SPF to your domain registrar's DNS control panel.
3. Add email addresses at your domain
Email addresses for your domain are added during the domain setup process. If you need to add additional email addresses at a later date, these can be added in the Settings → My email addresses screen. You may also choose to add a catch-all address if one was not already set up with the domain, so that any mail addressed to your domain comes to you, no matter what address is used.
You can customize other settings, such as your signature and default address, on the Settings → Signatures & Compose screen.
Optional domain setup
System email addresses
The email standard requires that the email address postmaster@yourdomain.com be a valid email address. Because of this, even if you don't set that address up, we will deliver any email sent to that address to the owner of the domain.
It's also best practice to support abuse@yourdomain.com. By default, if you don't set up your own addresses for abuse@yourdomain.com, we'll automatically direct all email sent to abuse@yourdomain.com to our abuse handling system.
Subdomain addressing and mail routing
On the Settings → Domains screen, you can control subdomain addressing and mail routing. To see these options, click the Edit button next to your domain, then find the Routing section and click Manage.
The Subdomain addressing options section lets you control how Fastmail handles subdomain addressing for your domain. For more information on subdomain addressing, please see our Plus addressing and subdomain addressing help page.
The Routing section lets you choose how mail to this domain is handled.
- Internal routing: Fastmail is handling all of your mail activities. This provides proper loop detection preventing inadvertent mail loops (via addresses or forwarding) that could cause spam or over-quota usage. While in this state, the DNS records for the domain are only checked every day.
- External routing: Some or all of your email activities are hosted elsewhere; whether this is the mail itself or things like mailing lists. No loop detection is possible. While in this state, the DNS records for the domain are checked every hour to see if they have changed.