A subdomain in AliasFleet is a prefix under a verified custom domain, such as mail.yourdomain.com, that holds its own aliases. This page covers adding a subdomain, adding its single MX record, verifying DNS, and using the subdomain for aliases. A verified root domain is required before a subdomain is added.
A verified root domain on the account is required, added as described in the DNS verification guide. DNS settings access is also required, at the registrar or at the DNS provider that manages the root domain. A subdomain prefix is chosen before setup starts, for example mail, work, or promo.
What is a subdomain in AliasFleet?#
A subdomain is a prefix attached to a verified root domain, forming a separate address space under that domain. For a root domain of yourdomain.com, mail.yourdomain.com is a subdomain, and aliases on it take the form newsletter@mail.yourdomain.com. Aliases on a subdomain forward to the destination inbox set for each alias, as aliases on the root domain do, and each subdomain is managed separately from the root domain and from other subdomains.
Subdomains group aliases by purpose while keeping one root domain and one brand. Typical groupings include personal.yourdomain.com for personal aliases, work.yourdomain.com for professional aliases, and promo.yourdomain.com for newsletters and sign-ups. The grouping is organisational: the root domain stays uncluttered, and each alias group sits under its own prefix.
How do I add a subdomain?#
A subdomain is added from the Domains section, under an existing verified root domain. The steps are:
- Open Domains: Go to Domains, select Add Domain, then select Add Subdomain.
- Select the root domain: Select the verified root domain the subdomain will sit under.
- Enter the prefix: Enter the subdomain prefix, for example mail for mail.yourdomain.com.
- Copy the MX record: The setup page shows the MX record value for the subdomain. Copy that value exactly as shown, for use in the next step.
No SPF, DKIM, or DMARC records are created at this stage. Those records belong to the parent domain and pass to the subdomain by inheritance, as described in the next section.
What DNS record does a subdomain need?#
A subdomain needs one DNS record only: an MX record. SPF, DKIM, and DMARC are inherited from the parent domain, so no separate records of those types are added for the subdomain.
| Record Type | Name | Value | Priority |
|---|---|---|---|
| MX | The subdomain prefix, for example mail for mail.yourdomain.com | As shown on the setup page | As shown on the setup page (usually 10) |
Add the MX record at the registrar or DNS provider that manages the root domain, using the name, value, and priority shown on the setup page. The value on the setup page is the authoritative value for that subdomain: values from another domain, or from a guide for a different setup, do not apply. For the full record-by-record walkthrough of domain DNS setup, see DNS Verification.
How do I verify a subdomain?#
Verification confirms that the MX record is in place and resolving. After the record has been added and has propagated, select Verify DNS on the setup page. A passing check confirms the subdomain is working and ready for aliases. If verification does not pass, run the checks in the troubleshooting section below before retrying, and see the DNS Not Verifying guide, which covers verification failures in full.
How do I use a subdomain on aliases?#
After the subdomain is active, it appears in the domain selector when a new alias is created. Select the subdomain there, in the same way as a root domain, and complete alias creation. Mail sent to an alias on the subdomain forwards to the destination inbox set for that alias.
For a walkthrough of alias creation on a custom domain, see How to Set Up Email Aliases on a Custom Domain.
How do I remove a subdomain?#
A subdomain is removed under the same rules as any domain, as described in Removing a Domain. Removal is independent: the parent domain and other subdomains are unaffected. Aliases on the removed subdomain stop working after removal is complete, so aliases still in use elsewhere must be moved or replaced before removal.
What if DNS verification fails?#
Verification failure most often comes from the record itself, not from the subdomain setup. Run these checks in order:
- Check the MX name: Confirm the name field holds the subdomain prefix only, for example mail, matching the format shown on the setup page.
- Check the value: Confirm the value was copied exactly from the setup page, with no extra characters and no missing characters.
- Check the record type: Confirm the record added is an MX record. SPF, DKIM, and DMARC records do not substitute for the MX record, even though those records exist on the parent domain.
- Retry after propagation: If the record was only just added, wait for it to propagate, then select Verify DNS again on the setup page.
- Follow the failure guide: If verification still fails after these checks, work through DNS Not Verifying, which covers verification failures step by step.