Configuring your domain with NS/MX
With this option, we host your DNS and automatically make sure all the correct entries are set for your email.
- This is the easiest, most commonly used option for domain hosting with Fastmail
- 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's DNS 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.
We provide a control panel for full customisation of your DNS records should you need it. Our nameservers are fast, reliable and secure. Our web interface for managing DNS is simple, but still powerful enough to allow any number of records of any type.
There's just three simple steps to set up your domain:
1. Add your domain
- Go to the Settings → Domains screen. .
Add your domain(s) (e.g.
mydomain.com). Using the "Add Domain" button brings up the new domain screen. Type your domain into the text box.
2. Domain registration configuration
Note: Updating your DNS is a high visibility change: we recommend updating it during a time when your site has low traffic
- Log in to the control panel supplied by your domain registrar.
Then look for where you can change the "name servers" for your domain. You want to make sure there are only two values, and that the two values are:
3. Add email addresses at your domain
To set up email addresses for your custom domain, add aliases at Settings → Users & Aliases. Add as many as you need, you may also choose to add a catchall alias so any mail addressed to your domain comes to you, no matter what address is used.
Creating an alias also creates a matching account identity. This lets you send mail from your account using the email address matching that alias. You can customise other settings too, such as your signature.
If you'd like to configure your account to primarily send using one of your custom domain addresses:
- Navigate to the Settings → Identities & Fetch screen.
- Select your alias in the "Compose new messages from
You can also select an identity to use as the default account to use for mail being sent from within a given folder.
Depending on the TTL values for your previous DNS settings (if any), it may take up to a day for the changes to propagate across the internet. Normally it's a lot faster: just a matter of minutes. Messages sent to the addresses you added on the aliases screen should now arrive in your Inbox.
Optional domain configuration
System email addresses
The email standard requires that the email address
firstname.lastname@example.org be a valid email address. Because of this, even if you don't set up an alias for that address, we will deliver any email sent to that address to the owner of the domain.
It's also best practice to support
email@example.com. By default, if you don't set up your own alias for
firstname.lastname@example.org, we'll automatically direct all email sent to
email@example.com to our automated abuse handling system.
Subdomain addressing and mail routing
On the Settings → Domains screen, you can control subdomain addressing and mail routing.
The Mail: Subdomain section lets you control how Fastmail handles subdomain addressing for your domain. There are three options:
- Subdomain addresses are handled like regular Fastmail domains, following plus addressing rules. (Recommended for ultimate flexibility)
- The subdomain portion is ignored.
- Mail to subdomains is disabled for your domain. This can mean two things:
- If the DNS for a subdomain points to us, then sending to that subdomain will be rejected and bounced.
- If the DNS for a subdomain points to other servers, then sending to that subdomain will direct email to the appropriate servers.
The Mail: Routing section lets you choose how mail to this domain is handled. Use:
- Internal routing when Fastmail is handling all of your mail activities. This provides proper loop detection preventing inadvertent mail loops (via aliases 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 when 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.