IP to Domain Lookup

Finding Domains Hosted on an IP Address

IP to domain lookup (also called reverse IP lookup) identifies all domain names hosted on a specific IP address. This technique is valuable for security research, competitive analysis, and server investigation.

How Reverse IP Lookup Works

1. An IP address is submitted to the lookup service
2. The service checks its database of DNS records for domains pointing to that IP
3. All matching domains are returned in the results
4. Additional information like hosting provider and server details may be included

Use Cases

Security Analysis

• Identify other domains on the same server as a suspicious website
• Discover related phishing or malware domains sharing infrastructure
• Map out attack infrastructure used by threat actors
• Assess risk from "bad neighbors" on shared hosting

Competitive Research

• Find what other websites a company hosts on the same server
• Discover hidden brands or projects sharing infrastructure
• Understand a competitor's hosting setup

SEO Analysis

• Check if your site shares an IP with spammy websites
• Assess the neighborhood quality of your hosting environment
• Identify potential negative SEO impact from co-hosted sites

Server Administration

• Audit all domains hosted on your servers
• Identify unauthorized domains pointing to your IP
• Plan server migrations by knowing all affected domains

Understanding the Results

• Shared Hosting: Hundreds or thousands of domains may share one IP
• Dedicated/VPS: Fewer domains, usually owned by the same entity
• CDN IPs: May show thousands of unrelated domains behind the same CDN
• Cloud IPs: May be reassigned between customers, so historical data can be misleading

Related Techniques

• PTR Records: Reverse DNS records map IPs to hostnames
• ASN Lookup: Find all IP ranges owned by an organization
• SSL Certificate Lookup: Certificates may list multiple domains (SAN entries)
• DNS History: Track what domains pointed to an IP over time