DNS-06 / DNS RECORDS
PTR Lookup
Reverse DNS — find the hostname an IP address resolves back to.
About the PTR Lookup
A PTR record is reverse DNS — it maps an IP address back to a hostname. Mail servers rely on PTR records to verify sending IPs, and a missing or mismatched PTR is a frequent cause of email being rejected. This tool performs a reverse lookup on any IP.
What this tool checks
It performs a reverse DNS lookup on the IP address you enter and returns the PTR record — the hostname that IP claims to be.
Why PTR matters for email
Receiving mail servers check that a sending IP's PTR record resolves and ideally matches the forward DNS. Missing or generic PTR records make your mail look suspicious and hurt deliverability.
Frequently asked questions
What is a PTR record?
A PTR (pointer) record maps an IP address to a hostname — the reverse of an A record. It's the basis of reverse DNS lookups.
Why do mail servers need a PTR record?
Many receiving servers reject or downgrade mail from IPs without a valid PTR record, since legitimate mail servers almost always have proper reverse DNS. A matching forward and reverse record signals a trustworthy sender.
How do I set up a PTR record?
PTR records are managed by whoever controls the IP block — usually your hosting provider or ISP, not your domain registrar. You'll need to request the PTR entry through them.