How to isolate high-risk sends by subdomain?

Isolating high-risk sends requires creating dedicated subdomains with their own authentication records and treating them as separate sending identities.

First, choose a subdomain that clearly distinguishes the mail stream, such as promo.tidalmail.com for aggressive marketing or outreach.tidalmail.com for prospecting. Configure separate SPF, DKIM, and DMARC records for each.

Warm the subdomain independently, starting with small volumes to engaged recipients. Monitor its reputation separately from your main sending domains. If the risky campaign damages reputation, only that subdomain suffers.

Think of high-risk subdomains as scouting vessels sent into uncertain waters. If they encounter trouble, your main fleet remains safely in port with their records intact.