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Reverse IP Lookup

Reverse DNS, hosting detection, and network details.

Reverse IP lookup maps an IP address back to its PTR (reverse DNS) hostname and network details. It reveals who owns or operates the IP — useful for identifying hosting providers, CDNs, and cloud infrastructure.

This tool returns the reverse DNS hostname (PTR record), whether the IP belongs to a hosting/datacenter provider, the organization name, and ASN. It does not enumerate all domains hosted on a shared IP — for that you would need a dedicated reverse-IP database service.

Useful for security research, network troubleshooting, and verifying whether traffic is routed through a CDN, VPN, or cloud provider.

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Common questions

Reverse DNS (PTR) maps an IP address back to a hostname. This tool looks up that PTR and adds hosting/ASN context. It does not list every website sharing a shared-hosting IP.

Many receivers expect outbound mail servers to have a sensible PTR that matches the SMTP hostname. Missing or generic PTR values commonly hurt deliverability.

No. That requires commercial co-hosting databases. Use this tool for network identity (PTR, org, ASN), then WHOIS or DNS tools for domain-specific checks.

What reverse IP lookup shows

Forward DNS maps a hostname to an IP. Reverse DNS (a PTR record) maps an IP back to a hostname. This tool queries that reverse mapping and enriches the result with organization and ASN hints so you can tell whether an address looks like a CDN edge, cloud VM, hosting provider, or residential/business allocation.

It does not list every website sharing a shared hosting IP — that requires commercial reverse-IP databases. What you get here is the network identity of the address: PTR hostname, hosting vs non-hosting signal, org name, and ASN.

When reverse lookup helps

  • Confirming whether traffic originates from a known cloud or CDN network during incident response
  • Checking that your mail server’s PTR matches the hostname you advertise in SMTP (broken PTR hurts deliverability)
  • Verifying a new VPS or load balancer received the reverse DNS you requested from the provider
  • Sanity-checking logs: an IP claiming to be “your CDN” should reverse to that provider’s naming pattern

How to read the results

Hostname / reverse DNS — the PTR value, if any. Many consumer and some cloud IPs have no PTR; that is normal for clients but undesirable for outbound mail servers.

Hosting signal — whether datasets classify the IP as datacenter/hosting. Useful as a hint, not a verdict: corporate offices and VPNs can look similar.

Organization / ASN — who announces the prefix. Cross-check with IP Geolocation when you need city/ISP context, or WHOIS for domain registration history.

Common problems

  • Mail deferred or junked because the sending IP has no PTR or PTR does not match EHLO
  • Assuming shared-host reverse lookup will list all co-hosted domains (it will not)
  • Misreading a CDN edge PTR as the origin server location

Example scenario

A newsletter started landing in spam after a provider IP change. Reverse lookup showed the new IP still had a generic PTR (static.example-host.net) instead of mail.customerdomain.com. Updating PTR with the host and aligning SPF/DKIM restored inbox placement within a day.

Limitations

PTR data depends on the IP owner publishing reverse zones. Geolocation and hosting labels are probabilistic. This is not a port scan and not a full domain co-hosting search. For broader site posture, run the Website Health Check.

Related resources

IP Geolocation · DNS Lookup · Domain Health Guide · Fix Email After DNS Migration