Reverse DNS lookup

Find the hostname associated with an IP address

What is reverse DNS? While normal DNS turns a domain into an IP, reverse DNS does the opposite — it looks up the hostname (PTR record) an IP address resolves back to. Useful for identifying mail servers, verifying server ownership, or investigating suspicious traffic.
Enter an IP address above to get started.

Why reverse DNS matters for email

Receiving mail servers check that the sending IP has a PTR record, and ideally that the name it points to resolves back to the same IP (forward-confirmed reverse DNS). A missing or generic PTR — like the ones home connections have — is a strong spam signal, and Gmail and Microsoft reject or junk mail from servers without one.

Who sets the PTR record?

Not your domain’s DNS host. The PTR record belongs to whoever owns the IP address block — your internet provider or hosting company. Most hosting panels (Hetzner, OVH, AWS and others) let you set it yourself; for a business line, ask your provider. Set it to the mail server’s name, e.g. mail.example.com, and make sure that name has an A record with the same IP.

No result?

Many IPs simply have no PTR record — common for home connections, unused addresses and some cloud servers. That isn’t an error unless the IP sends email.