Chapter · DMARC for Postmark
    Revised 17 Jun 2026
    Guide · DMARC · Postmark

    How to set up DMARC for Postmark.

    Postmark is a transactional-only ESP with strict acceptable-use enforcement. Their authentication setup is the simplest of the major ESPs.

    Afsan Rahmatullah
    Afsan RahmatullahMailerMonk

    DMARC (RFC 7489) tells receiving mail servers what to do when a message claiming to be from your domain fails SPF or DKIM. You publish exactly one DMARC record at `_dmarc.<your-domain>`, regardless of which ESP you use — DMARC is a domain-level policy, not a per-sender configuration. Postmark doesn't run DMARC for you, but their SPF + DKIM setup is what makes your DMARC checks pass.

    Start every domain at `p=none` with a `rua` (aggregate report) address pointing somewhere you actually read. Watch the reports for two to four weeks to confirm 100% of legitimate mail is aligned, then progress to `p=quarantine` and finally `p=reject`. Skipping the monitoring step is the single most common way founders accidentally block their own mail.

    Publish these DNS records

    Add the following record(s) to your domain's DNS zone. Most registrars (Cloudflare, Route 53, Namecheap, GoDaddy) accept values exactly as shown.

    Record · TXT
    Type
    TXT
    Host
    _dmarc
    Value
    v=DMARC1; p=none; rua=mailto:dmarc-reports@your-domain.com
    Why this matters
    • Postmark only sends transactional mail and signs with your domain's DKIM, so DMARC alignment is straightforward — most accounts can progress to `p=reject` quickly.

    Where in Postmark

    The DMARC configuration lives in Postmark → Sender Signatures → Add Domain → DNS.

    Verify the records

    Once published, run the DMARC Checker on your apex domain to confirm the record parses, reporting URIs are valid, and the policy is what you intended.

    From a terminal
    dig +short TXT _dmarc.your-domain.com
    Run the free DMARC checker

    Common pitfalls

    Pitfall
    • Postmark's anti-spam team will pause your account if you send marketing mail through it. Use a separate ESP for newsletters or promotional content.
    • The Return-Path on Postmark mail is `pm.mtasv.net` by default. Set up a custom Return-Path domain for SPF alignment if you need DMARC to pass on SPF as well as DKIM.
    After you publish

    Want to know if it actually keeps working?

    MailerMonk continuously watches your DMARC record, aggregate DMARC reports, and inbox placement — and pings you the moment something drifts. Free for the first domain.

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    About the author

    Afsan Rahmatullah
    Afsan Rahmatullah
    MailerMonk

    Building tools that keep cold email out of spam. Writes about deliverability, DMARC, and what actually moves inbox placement.

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