Many sales teams send cold email from a secondary domain so that a bad week in outreach does not hit the company's main domain, where invoices and support replies live.

The secondary domain still needs MX records, SPF, DKIM and DMARC of its own, plus a warm-up period and a clean list, exactly like the main one.

For a step-by-step version, uChecker has an email deliverability checklist for a new domain, from DNS records to the first sends.