Setting up your domain: NS/MX

With this option, we host your DNS and automatically make sure the rest of your DNS is set up correctly. All you need to do is point your nameservers to us — we take care of the rest.

  • This is the easiest, most commonly used option for domain hosting with Fastmail.
  • Not recommended for users with a website at the domain hosted elsewhere.
  • We'll automatically set up your domain so you can send and receive mail, sync contacts and calendars, and use the best security practices (DKIM, SPF, and more).
  • You will be able to manage your domain easily through your Fastmail settings. You can change your domain's DNS records to let you set up a website or use other services hosted elsewhere.
  • We can spot common set up errors and will alert you to any problems.

We provide a control panel for full customization of your DNS records if needed. Our nameservers are fast, reliable, and secure, and you can easily manage your DNS through our simple, but powerful, interface!

There's just three simple steps to set up your domain:

  1. Add your domain
  2. Update your NS records
  3. Add email addresses at your domain


Optional domain set up

We have handy guides for setting up your domain's nameserver records with a few common domain registrars:

1. Add your domain

We have a setup guide to help you get your domain working as quickly and easily as possible.

Go to the Settings → Domains screen. Then, add your domain(s) (e.g.

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 to continue adding your email addresses and setting up your domain. At the end, we will generate the instructions that match your situation. The general instructions for editing your nameserver records are below.

Please note: If you are on a legacy plan, the domain setup wizard can only set up email addresses, not users. You will need to add users manually in order to create additional user accounts at your custom domain.

2. Update your NS records

Note: Updating your DNS can take some time: we recommend updating it at a time you don't expect many emails.

  • Log in to the control panel supplied by your domain registrar. Usually, this will be the website from which you bought your domain.
  • Then, look for where you can change the nameservers 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

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 too, such as your signature.

If you'd like to set up your account to send using one of your custom domain addresses by default:


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 My email addresses screen should now arrive in your Inbox.

Optional domain set up

System email addresses

The email standard requires that the email address be a valid email address. Because of this, even if you don't set up that address, we will deliver any email sent to that address to the owner of the domain.

It's also best practice to support By default, if you don't set up your own address for, we'll automatically direct all email sent to to our abuse handling system.

Subdomain addressing and mail routing

On the Settings → Domains screen, you can control subdomain addressing and mail routing. Click on Edit next to your domain. In the Routing section, click on Manage.


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:
    1. If the DNS for a subdomain points to us, then sending to that subdomain will be rejected and bounced.
    2. 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 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 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.
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