Network Security

Discover Every Domain Sharing an IP Address

Reverse IP lookup reveals all domains hosted on a single IP address. In penetration testing, compromising one vulnerable site on shared hosting can expose neighboring targets. This tool maps the full co-hosting landscape, helping you assess lateral movement risk, identify shadow IT, and expand your reconnaissance scope.

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How It Works

From target input to actionable findings in three straightforward steps.

01

Enter an IP Address or Hostname

Provide an IPv4 address (e.g., 93.184.216.34) or a hostname (e.g., example.com). Hostnames are resolved to their IP address automatically before the reverse lookup begins.

02

Query Multiple Data Sources

The tool queries C99 reverse DNS databases and HackerTarget to enumerate all domains that resolve to the target IP. Results are de-duplicated and sorted for clarity.

03

Review Co-Hosted Domains and Network Info

Browse the list of domains sharing the IP, along with geolocation, ISP, ASN, and PTR record data. Use this to assess shared hosting risk, pivot to new targets, or identify infrastructure relationships.

Key Capabilities

Purpose-built scanning backed by real penetration testing expertise.

Multi-Source Enumeration

Queries multiple reverse DNS databases in parallel. When one source returns no results, fallback sources fill the gap, maximizing coverage across hosting providers.

IP Geolocation & ASN Data

Every lookup includes the IP geolocation (country, city, region), the hosting ISP, organization name, and Autonomous System Number (ASN) for network-level context.

PTR Record Resolution

Retrieves the reverse DNS (PTR) record for the IP, which often reveals the hosting provider, server role, or internal naming conventions.

Shared Hosting Risk Detection

Flags IPs with large numbers of co-hosted domains (50+), indicating shared hosting or CDN infrastructure where reverse IP results are less actionable for targeted recon.

Hostname-to-IP Resolution

Accepts hostnames as well as IP addresses. Enter a domain name and the tool resolves it first, then performs the reverse lookup on the resolved IP.

CDN & Cloud Provider Awareness

Identifies when an IP belongs to a CDN (Cloudflare, Akamai, AWS CloudFront) where thousands of unrelated domains share the same IP, and warns accordingly.

Common Use Cases

Map the full attack surface of a shared hosting environment to identify vulnerable co-hosted sites that could be leveraged for lateral movement
Discover shadow IT and forgotten domains hosted on corporate IP ranges that may not appear in official asset inventories
Identify all domains behind a suspicious IP address during incident response to assess the scope of a compromise
Verify hosting isolation during third-party security assessments to confirm sensitive applications are not co-hosted with untrusted sites
Expand reconnaissance scope by finding related domains and services hosted on the same infrastructure as the primary target
Assess supply chain risk by mapping which vendors and partners share hosting infrastructure with your organization

Why Use Pentestas

Security tools built by penetration testers, not just developers.

Enterprise-Grade Accuracy

Our scanning engine is built on the same methodologies our penetration testers use in manual engagements, tuned to minimize false positives and surface genuine risk.

Fast, Actionable Results

Get findings in minutes rather than days. Every result includes severity ratings, technical evidence, and clear remediation steps your team can act on immediately.

Continuous Monitoring

Schedule recurring scans from the Pentestas platform to catch regressions before they reach production. Stay ahead of new CVEs and configuration drift.

Privacy First

Your scan data is encrypted at rest and in transit. You own your data, with full control over retention and export.

Detailed Reporting

Export findings as PDF, CSV, or JSON. Feed results directly into your SIEM, ticketing system, or CI/CD pipeline through our REST API.

Instant Setup

Run scans directly from your browser. Enter a target, click scan, and receive results. Ready in under a minute.

Start scanning with Reverse IP Lookup today

Create a free account and run your first scan in under a minute. Full platform access during your 14-day trial.

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Frequently Asked Questions

Why does a CDN IP show thousands of domains?
Content Delivery Networks like Cloudflare, Akamai, and AWS CloudFront route traffic for millions of websites through shared IP addresses. A reverse lookup on a CDN IP returns all domains using that CDN edge node, which is not useful for targeted recon. The tool detects this and warns you when results indicate shared CDN infrastructure.
Can I look up IPv6 addresses?
Currently, the tool supports IPv4 addresses. IPv6 reverse lookup support is planned. You can enter a hostname that resolves to an IPv6 address, and the tool will use the IPv4 address if available.
How accurate is the domain list?
Reverse IP databases are compiled from DNS records, certificate transparency logs, and web crawls. They are comprehensive but not exhaustive. Domains that use DNS-based load balancing or recently changed their IP may not appear. For maximum coverage, combine reverse IP with subdomain enumeration and certificate transparency searches.
Why do some IPs return no domains?
Some IPs are not indexed by reverse DNS databases, especially those in small hosting environments, private infrastructure, or recently provisioned cloud instances. The tool queries multiple sources to maximize coverage, but gaps are possible.