How to create an inbound address on a custom domain

Once you have added and verified a custom domain in Cleanbox, you can create email addresses on it. Depending on your setup, these can be aliases (forwarded to your mailbox via IMAP) or relay addresses (filtered and forwarded to your own mail server via SMTP).

Option 1: Create an alias on your domain

Aliases are new email addresses that forward to your connected mailbox. They are receive-only and do not require you to have a mail server.

1. Navigate to Aliases in the sidebar
2. Click Add alias
3. In the domain dropdown, select your verified custom domain
4. Enter the local part (the part before the @, e.g. shop for shop@yourdomain.com)
5. Select which mailbox to forward messages to
6. Click Create

The alias is active immediately. Emails sent to this address will be filtered by Cleanbox and delivered to your mailbox via IMAP.

Requirements

• Your domain must be verified in Cleanbox
• MX records must point to mx1.cleanbox.to
• You need at least one connected mailbox as a delivery destination
• Your plan must include custom domains (Premium or higher)

Option 2: Create a relay address on your domain

Relay addresses protect your existing email addresses. Instead of creating new addresses, Cleanbox sits in front of your mail server and filters inbound email before forwarding it via SMTP.

1. Navigate to Domains in the sidebar
2. Click on your verified domain
3. Go to the Relay tab
4. Make sure Relay is enabled and your SMTP destination is configured
5. Click Add address
6. Enter the email address you want to protect (e.g. info@yourdomain.com)
7. Optionally set a custom spam threshold for this address
8. Click Save

Requirements

• Your plan must include Relay (Advanced or Enterprise)
• MX records must point to mx1.cleanbox.to
• Your SMTP destination (existing mail server) must be configured in the Relay settings

Aliases vs. Relay addresses

	Alias	Relay address
Purpose	Creates a new address	Protects an existing address
Delivery	IMAP upload to your mailbox	SMTP forward to your mail server
Mail server needed	No	Yes
Virus scanning	No	Yes (ClamAV)
Shield support	Yes	No
Minimum plan	Premium (3 domains)	Advanced (20 relay accounts)

DNS: the same for both

Both aliases and relay addresses require your domain MX records to point to Cleanbox. The DNS setup is identical — see DNS configuration guide for details.

The difference is what happens after Cleanbox receives the email: aliases deliver via IMAP to your connected mailbox, relay addresses forward via SMTP to your own mail server.