How to Authenticate a sending subdomain

Here is how to authenticate a sending subdomain, step by step.

The steps

Delegate a subdomain for sending, publish its own SPF, DKIM and DMARC, and warm it separately so its reputation is isolated from your root domain.

Why it matters

Getting this right is part of landing in the inbox instead of spam. See the full deliverability checklist.

How Rainmail helps

Rainmail sends from your own domain on a dedicated, isolated IP with SPF, DKIM, DMARC, reverse-DNS and managed warm-up handled for you, plus an AI that watches your list health and deliverability — and it welcomes the senders Amazon SES, SendGrid and Mailchimp reject, from $8. Run the free 10-second checker or see plans.