Sending provider

Postmark DMARC, DKIM and Return-Path setup

Postmark signs with a DKIM TXT record at a selector like 20131031155228pm._domainkey and passes SPF on a custom Return-Path: a CNAME from pm-bounces to pm.mtasv.net. Your root SPF needs no Postmark include. For DMARC, keep aspf=r so the Return-Path subdomain aligns, and point rua at Postmark's free tool, which emails a readable digest every Monday.

Postmark

Records at a glance

SPF

No include on your root domain; the Return-Path CNAME carries SPF

DKIM

TXT at <timestamp>pm._domainkey, value from Postmark's DNS Settings

DMARC

Any policy with aspf=r; free weekly reports from dmarc.postmarkapp.com

Check Postmark on your domain

Enter the domain you send from: the check looks for the Postmark SPF include, its DKIM key and your DMARC record, and says what to fix.

Lookups go from your browser to Cloudflare's public DNS resolver.

DNS records

The Postmark records

Values in angle brackets are specific to your account; copy them from the provider. Hosts are relative to your domain, as most DNS panels expect them.

Good to know

Step by step

Add DKIM and the Return-Path in Postmark

  1. Open DNS Settingssource (opens the vendor's page in a new tab)

    On the Sender Signatures page, under your domain, select DNS Settings (or Add a DKIM DNS record)

  2. Publish the DKIM keysource (opens the vendor's page in a new tab)

    Add the Hostname and Value Postmark shows as a TXT record at your DNS host, with the host entered without your domain if the panel adds it

  3. Add the Return-Path CNAMEsource (opens the vendor's page in a new tab)

    Create a CNAME from pm-bounces (or your own alias) to pm.mtasv.net. On Cloudflare click the orange cloud so the record is DNS only

  4. Set it in Postmarksource (opens the vendor's page in a new tab)

    Back in DNS Settings, enter the alias in the Return-Path section

  5. Verifysource (opens the vendor's page in a new tab)

    Select Verify, or wait for the green check marks on Sender Signatures; DNS can take up to 48 hours

Where the records go

Field by field for the DNS panel your domain uses:

DMARC

DMARC with Postmark

DMARCA safe first record

TXT at _dmarc

v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com

Replace the address with a mailbox you read; move to p=quarantine when the reports show every sender passing.

Troubleshooting

Common Postmark errors and fixes

For cold email

Mailboxes that come with the DNS records done

If the domain is for cold outreach, keep Postmark on your main domain and send from separate domains. Outreach2day buys the domains, publishes SPF, DKIM and DMARC, creates the mailboxes and starts warmup, then sends your campaigns from its own sequencer or exports the mailboxes to Instantly or Smartlead.

Create mailboxesBook a call
  • SPF, DKIM and DMARC set for youOn every domain, checked after setup and kept in place
  • $2.50 a mailbox a month12-mailbox minimum; warmup and the sending engine included
  • 1,000+ mailboxesA volume price per mailbox, quoted on a call

Questions

Do I need an SPF record for Postmark?

Not on your root domain. Postmark checks SPF on the Return-Path domain, so add the pm-bounces CNAME to pm.mtasv.net instead. Postmark says an include:spf.mtasv.net on the root does nothing.

What is Postmark's DMARC tool?

A free service at dmarc.postmarkapp.com. You publish a DMARC record with the report address it gives you, and it emails a readable summary of the reports every Monday. It works for any domain, Postmark customer or not; the paid DMARC Digests plan is $14 a month per domain.

Why does Postmark mail fail SPF alignment?

Without a custom Return-Path the envelope sender is Postmark's own bounce domain, which passes SPF for Postmark but does not match your From domain. Add the Return-Path CNAME, keep aspf=r, and DMARC passes on SPF as well as DKIM.

What is the Postmark DKIM selector?

A timestamp followed by pm, such as 20131031155228pm._domainkey in Postmark's API example. Yours is shown in the domain's DNS Settings; enter it in the check above.

Sources

Postmark documentation, checked . Menus and values change; if a step differs, Postmark's own page is the reference.

Deliverability call

Talk to our deliverability team

Book a call with the people who run our mailbox infrastructure. We look at your current setup and tell you what to change. Running 1,000+ mailboxes? We also quote a volume price below every vendor list price in our comparisons, warmup and sending included.

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