Free tool

PTR and rDNS checker for cold email

Check whether a custom SMTP or dedicated sending IP has reverse DNS that points to a hostname and resolves back to the same IP.

This checks PTR/rDNS and forward-confirmed reverse DNS for one domain. For a real launch verdict, run every domain, inbox, and tracking domain through the full QA pass.

Runs live in your browser via public DNS. Nothing is stored.

SMTP identity is visible before the first send

Custom SMTP paths and dedicated IPs need more than SPF and DKIM. Receiving systems can inspect the egress IP, its reverse DNS hostname, and whether forward DNS agrees with that reverse name.

This checker gives one public DNS read on that path. Use it before approving a self-hosted SMTP server, a dedicated provider IP, or a client-owned relay for outbound launch.

What to fix before launch

A missing PTR hostname is a blocker for custom SMTP launch. A PTR hostname that does not resolve back to the same IP is also a blocker. A generic provider hostname is usually a review item, especially when the campaign should present a branded sender identity.

For client signoff, pair this with SMTP banner alignment, SPF, DKIM, DMARC, blacklist checks, and tracking-domain SSL across every sending asset.

How to read the result

A pass means the IP has a PTR hostname and the hostname resolves back to the same IP. A warning means reverse DNS exists, but the hostname count or shape needs review. A fail means the egress identity should be fixed before launch.

What this check does not catch

A passing PTR/rDNS and forward-confirmed reverse DNS lookup is useful, but it is not launch signoff. Cold email campaigns still fail when adjacent records, tracking domains, or inbox-level settings are broken.

SPF records

DKIM selectors

DMARC policy

tracking-domain SSL

blacklist status

SMTP HELO/EHLO banner

Setup guides for this check

Read the setup notes behind this result, then verify the neighboring records before launch.

Google and Yahoo bulk sender requirements

SPF, DKIM, DMARC, one-click unsubscribe, and the spam-rate thresholds bulk senders must meet.

MX records and mail routing

How MX records route replies and bounces, provider records for Google and Microsoft, and common mistakes.

Email blacklists: check and delist

The RBLs that matter, how listings happen, how to check before launch, and the delisting process.

Need to check a full outbound workspace?

OutboundQA checks every domain, inbox, and tracking domain in the workspace, then gives you a shareable report with a Ready, Needs Fix, or Do Not Launch verdict.

Run a free workspace check View a sample report

Cold email launch checks to run next

Use this result as one checkpoint in the launch flow. Then verify the neighboring records and run the combined domain check before the outbound launch goes live.

SPF Checker

Look up a domain's SPF record and count its DNS lookups against the limit of 10.

DMARC Checker

Look up a domain's DMARC record and read its policy in plain English.

DKIM Checker

Look up a domain's DKIM selector and confirm the public key exists.

Auth Checker

Run SPF, DKIM, and DMARC together for a sending domain before launch.

MX Checker

Look up a domain's MX records and detect the mail provider.

Blacklist Checker

Check a domain and sampled mail server IPs against domain and email blocklists.

Reputation Checker

Check observable cold email reputation risks across age, blacklist, authentication, MX, and HTTPS signals.

Deliverability Checker

Check observable cold email infrastructure readiness across MX, SPF, DKIM, DMARC, blacklist, age, tracking-domain, and SMTP egress identity signals.

Receiver Checker

Check observable Gmail, Yahoo, and Microsoft sender requirements from public DNS and optional pasted message headers.

Recipient Preflight

Paste emails or domains and classify MX provider, free inboxes, security gateways, SPF, DMARC, and receive-mail readiness.

Tracking Checker

Check a branded cold email tracking domain for CNAME setup, DNS resolution, HTTPS, and redirect handoff.

MTA-STS Checker

Check MTA-STS and TLS-RPT records for inbound mail security posture before a cold email launch.

Launch Checklist

Generate a pre-launch QA checklist for domains, inboxes, authentication, tracking domains, blacklist checks, and signoff.

Domain Checker

Run MX, SPF, and DMARC in one pass for a quick readiness verdict on a sending domain.

Sample Launch QA Report

See the report founders, teams, and agencies can share after the full QA pass.

Email Deliverability Tool

See how one-off checks turn into pre-launch QA for full cold email workspaces.

Questions

It checks the reverse DNS hostname for an IPv4 address, then confirms whether that hostname resolves back to the same IP.

Enter the outbound SMTP egress IPv4 address used by your custom SMTP server or dedicated sending provider. You can also enter a hostname, and the checker will use its first IPv4 answer.

Forward-confirmed rDNS shows that the reverse hostname and forward DNS agree. For custom SMTP paths, mismatched or missing rDNS is a visible infrastructure risk.

No. PTR/rDNS is only one SMTP egress identity check. A launch signoff still needs SPF, DKIM, DMARC, blacklist status, tracking-domain checks, inbox setup, and receiver requirements.

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