How to Set Up Business Email on a Second Domain (Multi-Brand)

You launched a second brand, bought the .com to go with your .co.uk, or run two businesses from one desk. Each domain needs its own working email, but you do not want two of everything. This guide shows how to add a second domain to your email hosting, what DNS it needs, and how to decide between separate mailboxes and one inbox with two identities.

Quick answer

Add the second domain to the same email account, verify it, publish its own MX, SPF, DKIM and DMARC records, then either create mailboxes on it or attach its addresses as aliases to the mailboxes you already have. Every domain needs its own DNS records; the records from domain one do nothing for domain two.

Step by step

1. In your mail host's dashboard, add the domain. On OquMail the free plan allows 3 domains under one account, so a second and third brand cost nothing.
2. Prove you control it, usually by adding a TXT records (short text lines in DNS used for email security) the dashboard shows you. OquMail checks the record live and tells you when it is seen.
3. Publish the MX records (the settings that tell the internet where to deliver email for your domain) for the new domain: host @, value mail.oqumail.com, priority 10. Remove any MX left from the registrar's parking or forwarding service.
4. Publish SPF as a TXT at @: v=spf1 MX (Mail Exchanger — where incoming email is delivered) a:mail.oqumail.com ~all. Only one SPF record per domain.
5. Publish the DKIM TXT at the selector host your dashboard shows, and DMARC as a TXT at _dmarc: v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com, replacing the rua address with one you read.
6. Wait for the dashboard's verification to go green for all records, then create at least one mailbox (hello@newbrand.com) and send a test to a Gmail address. Open "Show original" there and confirm SPF, DKIM and DMARC all say PASS.

Mailboxes or aliases on the new domain?

• Separate mailboxes when the brands have different staff, different customers, or need separate archives for accounting or legal reasons.
• Aliases on existing mailboxes when the same person answers for both brands and you want one inbox. Add hello@newbrand.com as a sending identity in your mail app and reply as the brand the customer wrote to.
• A mix is normal: a shared support@ mailbox per brand, personal addresses on your primary domain only.

Keeping the brands from leaking into each other

• Set a separate signature per identity in your mail app; Thunderbird and Outlook support per-identity signatures.
• Create a server-side rule that labels or files mail by the To domain, so brand-two mail is visibly different in a shared inbox.
• Never reply to a brand-two customer from a brand-one address. Check the From field before sending, especially on a phone where the default identity is easy to miss.
• Use a different DMARC report address per domain if you want to see them separately, or one address for both if you prefer a single weekly read.

Country domains and defensive domains

If you registered both yourbrand.com and a ccTLD such as yourbrand.co.ke (KeNIC) or yourbrand.co.uk (Nominet), decide which is the primary sending domain and make the other receive-only with aliases. A receive-only domain still needs an SPF record; publish v=spf1 -all on a domain that never sends so nobody can forge it. Do the same for any parked domain you own.

Common questions

Can two domains share one mailbox password?

A mailbox belongs to one domain, but a single mailbox can carry aliases from other verified domains on the same account, so one login can receive and send for both. That is usually what people mean by "sharing".

Do I need a separate DKIM key per domain?

Yes. DKIM is published per domain, so each domain has its own selector record. Your dashboard shows a different value for each; copy each one to the right domain's DNS.

What if the second domain is at a different registrar?

That is fine. DNS records go wherever that domain's nameservers are managed. The email host does not care which registrar you use, only that the records resolve.