Reverse DNS Lookup

Reverse DNS verifies PTR mapping from IP to hostname, which is important for mail trust, logging readability, and infrastructure hygiene.

What this tool checks

• PTR lookup result quality for the provided IP target.
• Hostname formatting sanity and result consistency indicators.
• Output structure suitable for abuse and deliverability investigations.

How to read the output

• Result Summary indicates whether reverse mapping exists and looks coherent.
• Overview quickly exposes null PTR, malformed labels, or mismatch clues.
• Technical Details should be reviewed when mail servers reject by rDNS policy.
• Raw Output helps verify exact PTR response for provider coordination.

Common failure patterns

1. Missing PTR records for sending IP pools reduce mailbox trust.
2. PTR hostname not aligning with forward DNS policy triggers warnings.
3. Legacy PTR values persist after IP reassignment.
4. Incorrect zone delegation on in-addr.arpa causes intermittent lookup behavior.

Remediation workflow

1. Coordinate PTR updates with the IP range owner or upstream provider.
2. Align reverse hostname with forward DNS naming policy where possible.
3. Re-test after delegation or PTR edits have propagated.
4. Confirm mail-server banner and HELO naming strategy also aligns.

Next steps

• IP Information Lookup
• DNS Lookup (NsLookup)
• Back to DNS category

FAQ

Why is reverse DNS important for email?

Many receivers use PTR coherence as part of trust and spam filtering decisions.

Can one IP have multiple PTR records?

Technically possible, but a single stable PTR is usually preferred for operational clarity.

Who controls PTR updates?

Usually the IP block owner or upstream hosting/network provider.

Does PTR mismatch always block traffic?

No, but it increases risk of policy-based rejection, especially in mail workflows.

Should I verify forward DNS too?

Yes. Reverse and forward coherence is a common trust requirement.