Check TLS-RPT

Email addresses work too — everything after the @ is used.

How it works

_smtp._tls.acme.co
RECORDv=TLSRPTv1; rua=mailto:tls@acme.coVALID
RUAtls@acme.coMAILTO
MTA-STSv=STSv1; id=2026090801PUBLISHED
MXaspmx.l.google.comCOVERED
TLS-RPT is only useful when there is a policy to report against. Check both together.
01

Lookup

The TXT record at _smtp._tls. is fetched over DNS-over-HTTPS from your browser.

02

Parse

Tags are split on semicolons. The version must be TLSRPTv1 and rua must hold at least one mailto: or https: address.

03

Context

MTA-STS and MX are checked at the same time, because a report address with no policy behind it enforces nothing.

04

Verdict

Valid, needs attention, or broken — with the corrected record ready to copy when nothing is published.

What TLS-RPT does

When a sending server tries to deliver to you and the TLS handshake fails — expired certificate, hostname mismatch, a policy it cannot fetch — it has no way to tell you. The mail either falls back to plaintext or is not delivered at all, and both are invisible from your side. TLS-RPT gives receivers an address to send a daily summary of those failures, so you find out about a broken certificate on an MX from the report rather than from a client asking why mail stopped.

Why it goes with MTA-STS

MTA-STS is the policy that says "only deliver to me over TLS, and only to these hosts". If that policy has a mistake in it, or a certificate lapses, a strict sender will refuse to deliver — and that is exactly the failure TLS-RPT reports. I publish them together on every domain I set up. Publishing MTA-STS in enforce mode without TLS-RPT is flying blind; publishing TLS-RPT without MTA-STS still catches opportunistic TLS failures, which is worth having, but it is only half the job.

What the report address needs

The mailbox at the rua address receives JSON attachments from Google, Microsoft and others every day for each domain. That is fine for one or two domains. Across a sending fleet of forty it is a lot of unread mail, which is why people point rua at a reporting service. If you do, the address still has to accept mail — a service that quietly lapsed means the record validates and the reports vanish.

Faults this catches

Two records at the same name, which receivers treat as none. A rua that is neither mailto nor https. A missing version tag or one placed after the rua. Reports pointed at a domain that has nothing to do with yours, which may be intentional but is worth a second look. And the most common one: a TLS-RPT record on a domain that has no MX, left over from a template applied to every zone in an account.

Frequently asked questions

What is a TLS-RPT record?

A TXT record at _smtp._tls.yourdomain that tells receiving mail servers where to send daily reports about TLS delivery failures. The format is v=TLSRPTv1; rua=mailto:address.

Do I need TLS-RPT for cold email?

It is not a deliverability signal in itself, but it is the only way to find out that an MTA-STS policy or a certificate on your mail host is silently breaking inbound delivery. On domains that receive replies, yes.

Can rua be an https URL?

Yes. RFC 8460 allows https: endpoints that accept a POST of the JSON report. Most people use mailto because it needs no server.

Why does the checker warn about MTA-STS?

Because TLS-RPT reports failures against a policy. Without MTA-STS, receivers still send reports about opportunistic TLS failures, but nothing is being enforced, so the record does less than people assume.

Who actually sends TLS reports?

Google and Microsoft send them for every domain that publishes a record and receives mail from them. Smaller providers vary. Expect at least one report a day per domain from Google alone.

Last reviewed

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The diagnostics here are free and always will be. When the fix is bigger than a DNS record, this is the work I do.

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Bring a domain and the symptom. I will tell you what is actually wrong and whether you need me at all — plenty of people leave that call able to fix it themselves.

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We will run the checks together on your actual domains, and you will leave knowing what is broken, what it takes to fix, and what it should cost. If that is a job you can do in-house, I will say so.

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